diff --git a/CHANGES b/CHANGES
index be938951cb5..08fd505258f 100644
--- a/CHANGES
+++ b/CHANGES
@@ -8,6 +8,14 @@ current
 -------
 - *Insert changes/features/fixes for next release here*
 
+tmuxp 1.7.0a1 (2020-11-07)
+--------------------------
+- :issue:`530` Add plugin system for user customization of tmuxp
+- :issue:`530` Add tests for the plugin system
+- :issue:`530` Update existing tests for the plugin system
+- :issue:`530` Add the plugin interface to the tmuxp package
+- :issue:`530` Add in depth documentation for the plugin system
+
 tmuxp 1.6.1 (2020-11-07)
 ------------------------
 - :issue:`641` Improvements to ``shell``
diff --git a/README.rst b/README.rst
index dc9f150d305..99a2bf25a46 100644
--- a/README.rst
+++ b/README.rst
@@ -155,7 +155,6 @@ Snapshot your tmux layout, pane paths, and window/session names.
 
 See more about `freezing tmux`_ sessions.
 
-
 Convert a session file
 ----------------------
 
@@ -176,6 +175,11 @@ You can auto confirm the prompt. In this case no preview will be shown.
    $ tmuxp convert -y filename
    $ tmuxp convert --yes filename
 
+Plugin System
+-------------
+
+tmuxp has a plugin system to allow for custom behavior. See more about the 
+`Plugin System`_. 
 
 Docs / Reading material
 -----------------------
@@ -200,6 +204,7 @@ Want to learn more about tmux itself? `Read The Tao of Tmux online`_.
 .. _teamocil: https://github.com/remiprev/teamocil
 .. _Examples: http://tmuxp.git-pull.com/examples.html
 .. _freezing tmux: http://tmuxp.git-pull.com/cli.html#freeze-sessions
+.. _Plugin System: http://tmuxp.git-pull.com/plugin_system.html
 .. _bootstrap_env.py: https://github.com/tmux-python/tmuxp/blob/master/bootstrap_env.py
 .. _testing: http://tmuxp.git-pull.com/developing.html#test-runner
 .. _python objects: http://tmuxp.git-pull.com/api.html#api
diff --git a/docs/index.rst b/docs/index.rst
index fc6d6779547..6f1a1919c3b 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -28,6 +28,7 @@ Table of Contents
     quickstart
     examples
     cli
+    plugin_system
     developing
     api
     history
diff --git a/docs/plugin_system.rst b/docs/plugin_system.rst
new file mode 100644
index 00000000000..8cf50b44eda
--- /dev/null
+++ b/docs/plugin_system.rst
@@ -0,0 +1,130 @@
+.. _plugin_system:
+
+=============
+Plugin System
+=============
+
+The plugin system allows users to customize and extend different aspects of 
+tmuxp without the need to change tmuxp itself. 
+
+
+Using a Plugin
+--------------
+
+To use a plugin, install it in your local python environment and add it to 
+your tmuxp configuration file. 
+
+Example Configurations
+^^^^^^^^^^^^^^^^^^^^^^
+YAML
+~~~~
+
+.. literalinclude:: ../examples/plugin-system.yaml
+    :language: yaml
+
+JSON
+~~~~
+
+.. literalinclude:: ../examples/plugin-system.json
+    :language: json
+
+.. _poetry: https://python-poetry.org/
+
+
+Developing a Plugin
+-------------------
+
+tmuxp expects all plugins to be class within a python submodule named 
+``plugin`` that is within a python module that is installed in the local 
+python environment. A plugin interface is provided by tmuxp to inherit. 
+
+`poetry`_ is the chosen python package manager for tmuxp. It is highly 
+suggested to use it when developing plugins; however, ``pip`` will work 
+just as well. Only one of the configuration files is needed for the packaging 
+tool that the package developer desides to use. 
+
+.. code-block:: bash
+
+    python_module
+    ├── tmuxp_plugin_my_plugin_module
+    │   ├── __init__.py
+    │   └── plugin.py
+    ├── pyproject.toml  # Poetry's module configuration file
+    └── setup.py        # pip's module configuration file
+
+
+When publishing plugins to pypi, tmuxp advocates for standardized naming: 
+``tmuxp-plugin-{your-plugin-name}`` to allow for easier searching. To create a 
+module configuration file with poetry, run ``poetry init`` in the module 
+directory. The resulting file looks something like this:
+
+.. code-block:: toml
+
+    [tool.poetry]
+    name = "tmuxp-plugin-my-tmuxp-plugin"
+    version = "0.0.2"
+    description = "An example tmuxp plugin."
+    authors = ["Author Name <author.name@<domain>.com>"]
+
+    [tool.poetry.dependencies]
+    python = "~2.7 || ^3.5"
+    tmuxp = "^1.6.0"
+
+    [tool.poetry.dev-dependencies]
+
+    [build-system]
+    requires = ["poetry>=0.12"]
+    build-backend = "poetry.masonry.api"
+
+
+The `plugin.py` file could contain something like the following:
+
+.. code-block:: python
+    
+    from tmuxp.plugin import TmuxpPlugin
+    import datetime
+
+    class MyTmuxpPlugin(TmuxpPlugin):
+        def __init__(self):
+            """
+            Initialize my custom plugin.
+            """
+            # Optional version dependency configuration. See Plugin API docs 
+            # for all supported config parameters
+            config = {
+                'tmuxp_min_version' = '1.6.2'
+            }
+
+            TmuxpPlugin.__init__(
+                self,
+                plugin_name='tmuxp-plugin-my-tmuxp-plugin',
+                **config
+            )
+
+        def before_workspace_builder(self, session):
+            session.rename_session('my-new-session-name')
+
+        def reattach(self, session):
+            now = datetime.datetime.now().strftime('%Y-%m-%d')
+            session.rename_session('session_{}'.format(now))
+
+
+Once this plugin is installed in the local python environment, it can be used
+in a configuration file like the following:
+
+.. code-block:: yaml
+
+    session_name: plugin example
+    plugins:
+    - my_plugin_module.plugin.MyTmuxpPlugin
+    # ... the rest of your config
+
+
+Plugin API
+----------
+
+.. automethod:: tmuxp.plugin.TmuxpPlugin.before_workspace_builder
+.. automethod:: tmuxp.plugin.TmuxpPlugin.on_window_create
+.. automethod:: tmuxp.plugin.TmuxpPlugin.after_window_finished
+.. automethod:: tmuxp.plugin.TmuxpPlugin.before_script
+.. automethod:: tmuxp.plugin.TmuxpPlugin.reattach
\ No newline at end of file
diff --git a/examples/plugin-system.json b/examples/plugin-system.json
new file mode 100644
index 00000000000..4309676b309
--- /dev/null
+++ b/examples/plugin-system.json
@@ -0,0 +1,24 @@
+{
+  "session_name": "plugin-system",
+  "plugins": [
+    "tmuxp_plugin_extended_build.plugin.PluginExtendedBuild"
+  ],
+  "windows": [
+    {
+      "window_name": "editor",
+      "layout": "tiled",
+      "shell_command_before": [
+        "cd ~/"
+      ],
+      "panes": [
+        {
+          "shell_command": [
+            "cd /var/log",
+            "ls -al | grep *.log"
+          ]
+        },
+        "echo \"hello world\""
+      ]
+    }
+  ]
+}
\ No newline at end of file
diff --git a/examples/plugin-system.yaml b/examples/plugin-system.yaml
new file mode 100644
index 00000000000..13fa6278cee
--- /dev/null
+++ b/examples/plugin-system.yaml
@@ -0,0 +1,13 @@
+session_name: plugin-system
+plugins:
+- 'tmuxp_plugin_extended_build.plugin.PluginExtendedBuild'
+windows:
+- window_name: editor
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep *.log
+    - echo "hello world"
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index 1338e43e524..4c5a1345a88 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,7 +3,7 @@ skip-string-normalization = true
 
 [tool.poetry]
 name = "tmuxp"
-version = "1.6.1"
+version = "1.7.0a1"
 description = "tmux session manager"
 license = "MIT"
 authors = ["Tony Narlock <tony@git-pull.com>"]
@@ -69,6 +69,12 @@ pytest-mock = [
   {version="<3.0.0", python="<3"},
   {version="*", python=">=3"}
 ]
+tmuxp-test-plugin-bwb = { path = "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/"}
+tmuxp-test-plugin-bs = { path = "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/"}
+tmuxp-test-plugin-r = { path = "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/"}
+tmuxp-test-plugin-owc = { path = "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/"}
+tmuxp-test-plugin-awf = { path = "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/"}
+tmuxp-test-plugin-fail = { path = "tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/"}
 
 ### Coverage ###
 codecov = "*"
diff --git a/tests/fixtures/pluginsystem/__init__.py b/tests/fixtures/pluginsystem/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/partials/__init__.py b/tests/fixtures/pluginsystem/partials/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/partials/all_pass.py b/tests/fixtures/pluginsystem/partials/all_pass.py
new file mode 100644
index 00000000000..a19ade914ab
--- /dev/null
+++ b/tests/fixtures/pluginsystem/partials/all_pass.py
@@ -0,0 +1,20 @@
+from .test_plugin_helpers import MyTestTmuxpPlugin
+
+
+class AllVersionPassPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmuxp-plugin-my-tmuxp-plugin',
+            'tmux_min_version': '1.8',
+            'tmux_max_version': '100.0',
+            'tmux_version_incompatible': ['2.3'],
+            'libtmux_min_version': '0.8.3',
+            'libtmux_max_version': '100.0',
+            'libtmux_version_incompatible': ['0.7.1'],
+            'tmuxp_min_version': '1.6.0',
+            'tmuxp_max_version': '100.0.0',
+            'tmuxp_version_incompatible': ['1.5.6'],
+            'tmux_version': '3.0',
+            'tmuxp_version': '1.6.0',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
diff --git a/tests/fixtures/pluginsystem/partials/libtmux_version_fail.py b/tests/fixtures/pluginsystem/partials/libtmux_version_fail.py
new file mode 100644
index 00000000000..8e7535cab1d
--- /dev/null
+++ b/tests/fixtures/pluginsystem/partials/libtmux_version_fail.py
@@ -0,0 +1,31 @@
+from .test_plugin_helpers import MyTestTmuxpPlugin
+
+
+class LibtmuxVersionFailMinPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'libtmux-min-version-fail',
+            'libtmux_min_version': '0.8.3',
+            'libtmux_version': '0.7.0',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
+
+
+class LibtmuxVersionFailMaxPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'libtmux-max-version-fail',
+            'libtmux_max_version': '3.0',
+            'libtmux_version': '3.5',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
+
+
+class LibtmuxVersionFailIncompatiblePlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'libtmux-incompatible-version-fail',
+            'libtmux_version_incompatible': ['0.7.1'],
+            'libtmux_version': '0.7.1',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
diff --git a/tests/fixtures/pluginsystem/partials/test_plugin_helpers.py b/tests/fixtures/pluginsystem/partials/test_plugin_helpers.py
new file mode 100644
index 00000000000..d58eca8dd85
--- /dev/null
+++ b/tests/fixtures/pluginsystem/partials/test_plugin_helpers.py
@@ -0,0 +1,20 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class MyTestTmuxpPlugin(TmuxpPlugin):
+    def __init__(self, config):
+        tmux_version = config.pop('tmux_version', None)
+        libtmux_version = config.pop('libtmux_version', None)
+        tmuxp_version = config.pop('tmuxp_version', None)
+
+        TmuxpPlugin.__init__(self, **config)
+
+        # WARNING! This should not be done in anything but a test
+        if tmux_version:
+            self.version_constraints['tmux']['version'] = tmux_version
+        if libtmux_version:
+            self.version_constraints['libtmux']['version'] = libtmux_version
+        if tmuxp_version:
+            self.version_constraints['tmuxp']['version'] = tmuxp_version
+
+        self._version_check()
diff --git a/tests/fixtures/pluginsystem/partials/tmux_version_fail.py b/tests/fixtures/pluginsystem/partials/tmux_version_fail.py
new file mode 100644
index 00000000000..19ffbb1e086
--- /dev/null
+++ b/tests/fixtures/pluginsystem/partials/tmux_version_fail.py
@@ -0,0 +1,32 @@
+from .test_plugin_helpers import MyTestTmuxpPlugin
+
+
+class TmuxVersionFailMinPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmux-min-version-fail',
+            'tmux_min_version': '1.8',
+            'tmux_version': '1.7',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
+
+
+class TmuxVersionFailMaxPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmux-max-version-fail',
+            'tmux_max_version': '3.0',
+            'tmux_version': '3.5',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
+
+
+class TmuxVersionFailIncompatiblePlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmux-incompatible-version-fail',
+            'tmux_version_incompatible': ['2.3'],
+            'tmux_version': '2.3',
+        }
+
+        MyTestTmuxpPlugin.__init__(self, config)
diff --git a/tests/fixtures/pluginsystem/partials/tmuxp_version_fail.py b/tests/fixtures/pluginsystem/partials/tmuxp_version_fail.py
new file mode 100644
index 00000000000..05cbd4ce059
--- /dev/null
+++ b/tests/fixtures/pluginsystem/partials/tmuxp_version_fail.py
@@ -0,0 +1,31 @@
+from .test_plugin_helpers import MyTestTmuxpPlugin
+
+
+class TmuxpVersionFailMinPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmuxp-min-version-fail',
+            'tmuxp_min_version': '1.6.0',
+            'tmuxp_version': '1.5.6',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
+
+
+class TmuxpVersionFailMaxPlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmuxp-max-version-fail',
+            'tmuxp_max_version': '2.0.0',
+            'tmuxp_version': '2.5',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
+
+
+class TmuxpVersionFailIncompatiblePlugin(MyTestTmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmuxp-incompatible-version-fail',
+            'tmuxp_version_incompatible': ['1.5.0'],
+            'tmuxp_version': '1.5.0',
+        }
+        MyTestTmuxpPlugin.__init__(self, config)
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/pyproject.toml b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/pyproject.toml
new file mode 100644
index 00000000000..198d239d631
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "tmuxp_test_plugin_awf"
+version = "0.0.2"
+description = "A tmuxp plugin to test after_window_finished part of the tmuxp plugin system"
+authors = ["Joseph Flinn <joseph.s.flinn@gmail.com>"]
+
+[tool.poetry.dependencies]
+python = "~2.7 || ^3.5"
+tmuxp = "^1.6.0"
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/tmuxp_test_plugin_awf/__init__.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/tmuxp_test_plugin_awf/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/tmuxp_test_plugin_awf/plugin.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/tmuxp_test_plugin_awf/plugin.py
new file mode 100644
index 00000000000..442f86e2677
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_awf/tmuxp_test_plugin_awf/plugin.py
@@ -0,0 +1,18 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class PluginAfterWindowFinished(TmuxpPlugin):
+    def __init__(self):
+        self.message = '[+] This is the Tmuxp Test Plugin'
+
+    def after_window_finished(self, window):
+        if window.name == 'editor':
+            window.rename_window('plugin_test_awf')
+        elif window.name == 'awf_mw_test':
+            window.rename_window('plugin_test_awf_mw')
+        elif window.name == 'awf_mw_test_2':
+            window.rename_window('plugin_test_awf_mw_2')
+        elif window.name == 'mp_test_owc':
+            window.rename_window('mp_test_awf')
+        else:
+            pass
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/pyproject.toml b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/pyproject.toml
new file mode 100644
index 00000000000..15cd0f2ff67
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "tmuxp_test_plugin_bs"
+version = "0.0.2"
+description = "A tmuxp plugin to test before_script part of the tmuxp plugin system"
+authors = ["Joseph Flinn <joseph.s.flinn@gmail.com>"]
+
+[tool.poetry.dependencies]
+python = "~2.7 || ^3.5"
+tmuxp = "^1.6.0."
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/tmuxp_test_plugin_bs/__init__.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/tmuxp_test_plugin_bs/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/tmuxp_test_plugin_bs/plugin.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/tmuxp_test_plugin_bs/plugin.py
new file mode 100644
index 00000000000..98692ac9f30
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bs/tmuxp_test_plugin_bs/plugin.py
@@ -0,0 +1,9 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class PluginBeforeScript(TmuxpPlugin):
+    def __init__(self):
+        self.message = '[+] This is the Tmuxp Test Plugin'
+
+    def before_script(self, session):
+        session.rename_session('plugin_test_bs')
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/pyproject.toml b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/pyproject.toml
new file mode 100644
index 00000000000..e34023ad100
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "tmuxp_test_plugin_bwb"
+version = "0.0.2"
+description = "A tmuxp plugin to test before_workspace_build part of the tmuxp plugin system"
+authors = ["Joseph Flinn <joseph.s.flinn@gmail.com>"]
+
+[tool.poetry.dependencies]
+python = "~2.7 || ^3.5"
+tmuxp = "^1.6.0"
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/tmuxp_test_plugin_bwb/__init__.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/tmuxp_test_plugin_bwb/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/tmuxp_test_plugin_bwb/plugin.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/tmuxp_test_plugin_bwb/plugin.py
new file mode 100644
index 00000000000..78fd68f28b0
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_bwb/tmuxp_test_plugin_bwb/plugin.py
@@ -0,0 +1,9 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class PluginBeforeWorkspaceBuilder(TmuxpPlugin):
+    def __init__(self):
+        self.message = '[+] This is the Tmuxp Test Plugin'
+
+    def before_workspace_builder(self, session):
+        session.rename_session('plugin_test_bwb')
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/pyproject.toml b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/pyproject.toml
new file mode 100644
index 00000000000..977cabeb3ea
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "tmuxp_test_plugin_fail"
+version = "0.1.0"
+description = "A test plugin designed to fail to test the cli"
+authors = ["Joseph Flinn <joseph.s.flinn@gmail.com>"]
+
+[tool.poetry.dependencies]
+python = "~2.7 || ^3.5"
+tmuxp = "^1.6.0"
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/tmuxp_test_plugin_fail/__init__.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/tmuxp_test_plugin_fail/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/tmuxp_test_plugin_fail/plugin.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/tmuxp_test_plugin_fail/plugin.py
new file mode 100644
index 00000000000..abe56e46c75
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_fail/tmuxp_test_plugin_fail/plugin.py
@@ -0,0 +1,10 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class PluginFailVersion(TmuxpPlugin):
+    def __init__(self):
+        config = {
+            'plugin_name': 'tmuxp-plugin-fail-version',
+            'tmuxp_max_version': '0.0.0',
+        }
+        TmuxpPlugin.__init__(self, **config)
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/pyproject.toml b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/pyproject.toml
new file mode 100644
index 00000000000..c6a94e5db1f
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "tmuxp_test_plugin_owc"
+version = "0.0.2"
+description = "A tmuxp plugin to test on_window_create part of the tmuxp plugin system"
+authors = ["Joseph Flinn <joseph.s.flinn@gmail.com>"]
+
+[tool.poetry.dependencies]
+python = "~2.7 || ^3.5"
+tmuxp = "^1.6.0"
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/tmuxp_test_plugin_owc/__init__.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/tmuxp_test_plugin_owc/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/tmuxp_test_plugin_owc/plugin.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/tmuxp_test_plugin_owc/plugin.py
new file mode 100644
index 00000000000..2ba059cd4d8
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_owc/tmuxp_test_plugin_owc/plugin.py
@@ -0,0 +1,18 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class PluginOnWindowCreate(TmuxpPlugin):
+    def __init__(self):
+        self.message = '[+] This is the Tmuxp Test Plugin'
+
+    def on_window_create(self, window):
+        if window.name == 'editor':
+            window.rename_window('plugin_test_owc')
+        elif window.name == 'owc_mw_test':
+            window.rename_window('plugin_test_owc_mw')
+        elif window.name == 'owc_mw_test_2':
+            window.rename_window('plugin_test_owc_mw_2')
+        elif window.name == 'mp_test':
+            window.rename_window('mp_test_owc')
+        else:
+            pass
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/pyproject.toml b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/pyproject.toml
new file mode 100644
index 00000000000..ae0b438dba2
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "tmuxp_test_plugin_r"
+version = "0.0.2"
+description = "A tmuxp plugin to test reattach part of the tmuxp plugin system"
+authors = ["Joseph Flinn <joseph.s.flinn@gmail.com>"]
+
+[tool.poetry.dependencies]
+python = "~2.7 || ^3.5"
+tmuxp = "^1.6.0"
+
+[tool.poetry.dev-dependencies]
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/tmuxp_test_plugin_r/__init__.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/tmuxp_test_plugin_r/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/tmuxp_test_plugin_r/plugin.py b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/tmuxp_test_plugin_r/plugin.py
new file mode 100644
index 00000000000..ccf251142a0
--- /dev/null
+++ b/tests/fixtures/pluginsystem/plugins/tmuxp_test_plugin_r/tmuxp_test_plugin_r/plugin.py
@@ -0,0 +1,9 @@
+from tmuxp.plugin import TmuxpPlugin
+
+
+class PluginReattach(TmuxpPlugin):
+    def __init__(self):
+        self.message = '[+] This is the Tmuxp Test Plugin'
+
+    def reattach(self, session):
+        session.rename_session('plugin_test_r')
diff --git a/tests/fixtures/workspacebuilder/plugin_awf.yaml b/tests/fixtures/workspacebuilder/plugin_awf.yaml
new file mode 100644
index 00000000000..5111833e14a
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_awf.yaml
@@ -0,0 +1,15 @@
+session_name: plugin-test-awf
+plugins:
+- 'tmuxp_test_plugin_awf.plugin.PluginAfterWindowFinished'
+windows:
+- window_name: editor
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+    - echo hello
+    - echo hello
+    - echo hello
diff --git a/tests/fixtures/workspacebuilder/plugin_awf_multiple_windows.yaml b/tests/fixtures/workspacebuilder/plugin_awf_multiple_windows.yaml
new file mode 100644
index 00000000000..994c2a7c4db
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_awf_multiple_windows.yaml
@@ -0,0 +1,18 @@
+session_name: plugin-test-awf-mw
+plugins:
+- 'tmuxp_test_plugin_awf.plugin.PluginAfterWindowFinished'
+windows:
+- window_name: awf_mw_test
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+- window_name: awf_mw_test_2
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - echo hello
\ No newline at end of file
diff --git a/tests/fixtures/workspacebuilder/plugin_bs.yaml b/tests/fixtures/workspacebuilder/plugin_bs.yaml
new file mode 100644
index 00000000000..a04d6eb3f30
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_bs.yaml
@@ -0,0 +1,15 @@
+session_name: plugin-test-bs
+plugins:
+- 'tmuxp_test_plugin_bs.plugin.PluginBeforeScript'
+windows:
+- window_name: editor
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+    - echo hello
+    - echo hello
+    - echo hello
diff --git a/tests/fixtures/workspacebuilder/plugin_bwb.yaml b/tests/fixtures/workspacebuilder/plugin_bwb.yaml
new file mode 100644
index 00000000000..8241f279462
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_bwb.yaml
@@ -0,0 +1,15 @@
+session_name: plugin-test-bwb
+plugins:
+- 'tmuxp_test_plugin_bwb.plugin.PluginBeforeWorkspaceBuilder'
+windows:
+- window_name: editor
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+    - echo hello
+    - echo hello
+    - echo hello
diff --git a/tests/fixtures/workspacebuilder/plugin_missing_fail.yaml b/tests/fixtures/workspacebuilder/plugin_missing_fail.yaml
new file mode 100644
index 00000000000..4e1097debd5
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_missing_fail.yaml
@@ -0,0 +1,6 @@
+session_name: plugin-test-missing-fail
+plugins:
+- 'tmuxp_test_plugin_fail.plugin.PluginFailMissing'
+windows:
+- panes:
+    - echo "hey"
\ No newline at end of file
diff --git a/tests/fixtures/workspacebuilder/plugin_multiple_plugins.yaml b/tests/fixtures/workspacebuilder/plugin_multiple_plugins.yaml
new file mode 100644
index 00000000000..113347db6e9
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_multiple_plugins.yaml
@@ -0,0 +1,14 @@
+session_name: plugin-test-multiple-plugins
+plugins:
+- 'tmuxp_test_plugin_bwb.plugin.PluginBeforeWorkspaceBuilder'
+- 'tmuxp_test_plugin_owc.plugin.PluginOnWindowCreate'
+- 'tmuxp_test_plugin_awf.plugin.PluginAfterWindowFinished'
+windows:
+- window_name: mp_test
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
\ No newline at end of file
diff --git a/tests/fixtures/workspacebuilder/plugin_owc.yaml b/tests/fixtures/workspacebuilder/plugin_owc.yaml
new file mode 100644
index 00000000000..abc81d9192f
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_owc.yaml
@@ -0,0 +1,15 @@
+session_name: plugin-test-owc
+plugins:
+- 'tmuxp_test_plugin_owc.plugin.PluginOnWindowCreate'
+windows:
+- window_name: editor
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+    - echo hello
+    - echo hello
+    - echo hello
diff --git a/tests/fixtures/workspacebuilder/plugin_owc_multiple_windows.yaml b/tests/fixtures/workspacebuilder/plugin_owc_multiple_windows.yaml
new file mode 100644
index 00000000000..c7d437e5847
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_owc_multiple_windows.yaml
@@ -0,0 +1,17 @@
+session_name: plugin-test-owc-mw
+plugins:
+- 'tmuxp_test_plugin_owc.plugin.PluginOnWindowCreate'
+windows:
+- window_name: owc_mw_test
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+- window_name: owc_mw_test_2
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - echo hello
\ No newline at end of file
diff --git a/tests/fixtures/workspacebuilder/plugin_r.yaml b/tests/fixtures/workspacebuilder/plugin_r.yaml
new file mode 100644
index 00000000000..b220aab6b83
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_r.yaml
@@ -0,0 +1,15 @@
+session_name: plugin-test-r
+plugins:
+- 'tmuxp_test_plugin_r.plugin.PluginReattach'
+windows:
+- window_name: editor
+  layout: tiled
+  shell_command_before:
+    - cd ~/
+  panes:
+    - shell_command:
+        - cd /var/log
+        - ls -al | grep \.log
+    - echo hello
+    - echo hello
+    - echo hello
diff --git a/tests/fixtures/workspacebuilder/plugin_versions_fail.yaml b/tests/fixtures/workspacebuilder/plugin_versions_fail.yaml
new file mode 100644
index 00000000000..e4e7a4910bf
--- /dev/null
+++ b/tests/fixtures/workspacebuilder/plugin_versions_fail.yaml
@@ -0,0 +1,6 @@
+session_name: plugin-test-version-fail
+plugins:
+- 'tmuxp_test_plugin_fail.plugin.PluginFailVersion'
+windows:
+- panes:
+    - echo "hey"
\ No newline at end of file
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 2741a30a2f7..627ab21e48a 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -7,6 +7,8 @@
 
 import pytest
 
+import kaptan
+
 import click
 from click.testing import CliRunner
 
@@ -20,7 +22,11 @@
     is_pure_name,
     load_workspace,
     scan_config,
+    _reattach,
+    load_plugins,
 )
+from tmuxp.workspacebuilder import WorkspaceBuilder
+from tmuxp_test_plugin_bwb.plugin import PluginBeforeWorkspaceBuilder
 
 from .fixtures._util import curjoin, loadfixture
 
@@ -953,3 +959,103 @@ def test_ls_cli(monkeypatch, tmpdir):
     runner = CliRunner()
     cli_output = runner.invoke(command_ls).output
     assert cli_output == '\n'.join(stems) + '\n'
+
+
+def test_load_plugins():
+    plugins_config = loadfixture("workspacebuilder/plugin_bwb.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(plugins_config).get()
+    sconfig = config.expand(sconfig)
+
+    plugins = load_plugins(sconfig)
+
+    assert len(plugins) == 1
+
+    test_plugin_class_types = [
+        PluginBeforeWorkspaceBuilder().__class__,
+    ]
+    for plugin in plugins:
+        assert plugin.__class__ in test_plugin_class_types
+
+
+@pytest.mark.skip('Not sure how to clean up the tmux session this makes')
+@pytest.mark.parametrize(
+    "cli_args,inputs",
+    [
+        (
+            ['load', 'tests/fixtures/workspacebuilder/plugin_versions_fail.yaml'],
+            ['y\n'],
+        )
+    ],
+)
+def test_load_plugins_version_fail_skip(cli_args, inputs):
+    runner = CliRunner()
+
+    results = runner.invoke(cli.cli, cli_args, input=''.join(inputs))
+    assert '[Loading]' in results.output
+
+
+@pytest.mark.parametrize(
+    "cli_args,inputs",
+    [
+        (
+            ['load', 'tests/fixtures/workspacebuilder/plugin_versions_fail.yaml'],
+            ['n\n'],
+        )
+    ],
+)
+def test_load_plugins_version_fail_no_skip(cli_args, inputs):
+    runner = CliRunner()
+
+    results = runner.invoke(cli.cli, cli_args, input=''.join(inputs))
+    assert '[Not Skipping]' in results.output
+
+
+@pytest.mark.parametrize(
+    "cli_args", [(['load', 'tests/fixtures/workspacebuilder/plugin_missing_fail.yaml'])]
+)
+def test_load_plugins_plugin_missing(cli_args):
+    runner = CliRunner()
+
+    results = runner.invoke(cli.cli, cli_args)
+    assert '[Plugin Error]' in results.output
+
+
+def test_plugin_system_before_script(server, monkeypatch):
+    # this is an implementation test. Since this testsuite may be ran within
+    # a tmux session by the developer himself, delete the TMUX variable
+    # temporarily.
+    monkeypatch.delenv('TMUX', raising=False)
+    session_file = curjoin("workspacebuilder/plugin_bs.yaml")
+
+    # open it detached
+    session = load_workspace(
+        session_file, socket_name=server.socket_name, detached=True
+    )
+
+    assert isinstance(session, libtmux.Session)
+    assert session.name == 'plugin_test_bs'
+
+
+def test_reattach_plugins(server):
+    config_plugins = loadfixture("workspacebuilder/plugin_r.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    # open it detached
+    builder = WorkspaceBuilder(
+        sconf=sconfig, plugins=load_plugins(sconfig), server=server
+    )
+    builder.build()
+
+    try:
+        _reattach(builder)
+    except libtmux.exc.LibTmuxException:
+        pass
+
+    proc = builder.session.cmd('display-message', '-p', "'#S'")
+
+    assert proc.stdout[0] == "'plugin_test_r'"
diff --git a/tests/test_config.py b/tests/test_config.py
index f8f027e25cd..e1085cf47b6 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -383,3 +383,23 @@ def test_replaces_env_variables(monkeypatch):
     assert "%s/moo" % env_val == sconfig['global_options']['default-shell']
     assert "%s/lol" % env_val == sconfig['options']['default-command']
     assert "logging @ %s" % env_val == sconfig['windows'][1]['window_name']
+
+
+def test_plugins():
+    yaml_config = """
+    session_name: test session
+    plugins: tmuxp-plugin-one.plugin.TestPluginOne
+    windows:
+    - window_name: editor
+      panes:
+      shell_command:
+      - tail -F /var/log/syslog
+      start_directory: /var/log
+    """
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(yaml_config).get()
+
+    with pytest.raises(exc.ConfigError) as excinfo:
+        config.validate_schema(sconfig)
+        assert excinfo.matches('only supports list type')
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
new file mode 100644
index 00000000000..488465e0bd1
--- /dev/null
+++ b/tests/test_plugin.py
@@ -0,0 +1,82 @@
+# -*- coding: utf-8 -*-
+"""Test for tmuxp plugin api."""
+from __future__ import absolute_import
+
+import pytest
+
+from tmuxp.exc import TmuxpPluginException
+
+from .fixtures.pluginsystem.partials.all_pass import AllVersionPassPlugin
+from .fixtures.pluginsystem.partials.libtmux_version_fail import (
+    LibtmuxVersionFailIncompatiblePlugin,
+    LibtmuxVersionFailMaxPlugin,
+    LibtmuxVersionFailMinPlugin,
+)
+from .fixtures.pluginsystem.partials.tmux_version_fail import (
+    TmuxVersionFailIncompatiblePlugin,
+    TmuxVersionFailMaxPlugin,
+    TmuxVersionFailMinPlugin,
+)
+from .fixtures.pluginsystem.partials.tmuxp_version_fail import (
+    TmuxpVersionFailIncompatiblePlugin,
+    TmuxpVersionFailMaxPlugin,
+    TmuxpVersionFailMinPlugin,
+)
+
+
+def test_all_pass():
+    AllVersionPassPlugin()
+
+
+def test_tmux_version_fail_min():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        TmuxVersionFailMinPlugin()
+    assert 'tmux-min-version-fail' in str(exc_info.value)
+
+
+def test_tmux_version_fail_max():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        TmuxVersionFailMaxPlugin()
+    assert 'tmux-max-version-fail' in str(exc_info.value)
+
+
+def test_tmux_version_fail_incompatible():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        TmuxVersionFailIncompatiblePlugin()
+    assert 'tmux-incompatible-version-fail' in str(exc_info.value)
+
+
+def test_tmuxp_version_fail_min():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        TmuxpVersionFailMinPlugin()
+    assert 'tmuxp-min-version-fail' in str(exc_info.value)
+
+
+def test_tmuxp_version_fail_max():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        TmuxpVersionFailMaxPlugin()
+    assert 'tmuxp-max-version-fail' in str(exc_info.value)
+
+
+def test_tmuxp_version_fail_incompatible():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        TmuxpVersionFailIncompatiblePlugin()
+    assert 'tmuxp-incompatible-version-fail' in str(exc_info.value)
+
+
+def test_libtmux_version_fail_min():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        LibtmuxVersionFailMinPlugin()
+    assert 'libtmux-min-version-fail' in str(exc_info.value)
+
+
+def test_libtmux_version_fail_max():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        LibtmuxVersionFailMaxPlugin()
+    assert 'libtmux-max-version-fail' in str(exc_info.value)
+
+
+def test_libtmux_version_fail_incompatible():
+    with pytest.raises(TmuxpPluginException, match=r'Incompatible.*') as exc_info:
+        LibtmuxVersionFailIncompatiblePlugin()
+    assert 'libtmux-incompatible-version-fail' in str(exc_info.value)
diff --git a/tests/test_workspacebuilder.py b/tests/test_workspacebuilder.py
index 4aab73dafe8..3783d0d8e4c 100644
--- a/tests/test_workspacebuilder.py
+++ b/tests/test_workspacebuilder.py
@@ -15,6 +15,7 @@
 from tmuxp import config, exc
 from tmuxp._compat import text_type
 from tmuxp.workspacebuilder import WorkspaceBuilder
+from tmuxp.cli import load_plugins
 
 from . import example_dir, fixtures_dir
 from .fixtures._util import loadfixture
@@ -673,3 +674,108 @@ def test_before_load_true_if_test_passes_with_args(server):
 
     with temp_session(server) as session:
         builder.build(session=session)
+
+
+def test_plugin_system_before_workspace_builder(session):
+    config_plugins = loadfixture("workspacebuilder/plugin_bwb.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    builder = WorkspaceBuilder(sconf=sconfig, plugins=load_plugins(sconfig))
+    assert len(builder.plugins) > 0
+
+    builder.build(session=session)
+
+    proc = session.cmd('display-message', '-p', "'#S'")
+    assert proc.stdout[0] == "'plugin_test_bwb'"
+
+
+def test_plugin_system_on_window_create(session):
+    config_plugins = loadfixture("workspacebuilder/plugin_owc.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    builder = WorkspaceBuilder(sconf=sconfig, plugins=load_plugins(sconfig))
+    assert len(builder.plugins) > 0
+
+    builder.build(session=session)
+
+    proc = session.cmd('display-message', '-p', "'#W'")
+    assert proc.stdout[0] == "'plugin_test_owc'"
+
+
+def test_plugin_system_after_window_finished(session):
+    config_plugins = loadfixture("workspacebuilder/plugin_awf.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    builder = WorkspaceBuilder(sconf=sconfig, plugins=load_plugins(sconfig))
+    assert len(builder.plugins) > 0
+
+    builder.build(session=session)
+
+    proc = session.cmd('display-message', '-p', "'#W'")
+    assert proc.stdout[0] == "'plugin_test_awf'"
+
+
+def test_plugin_system_on_window_create_multiple_windows(session):
+    config_plugins = loadfixture("workspacebuilder/plugin_owc_multiple_windows.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    builder = WorkspaceBuilder(sconf=sconfig, plugins=load_plugins(sconfig))
+    assert len(builder.plugins) > 0
+
+    builder.build(session=session)
+
+    proc = session.cmd('list-windows', '-F', "'#W'")
+    assert "'plugin_test_owc_mw'" in proc.stdout
+    assert "'plugin_test_owc_mw_2'" in proc.stdout
+
+
+def test_plugin_system_after_window_finished_multiple_windows(session):
+    config_plugins = loadfixture("workspacebuilder/plugin_awf_multiple_windows.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    builder = WorkspaceBuilder(sconf=sconfig, plugins=load_plugins(sconfig))
+    assert len(builder.plugins) > 0
+
+    builder.build(session=session)
+
+    proc = session.cmd('list-windows', '-F', "'#W'")
+    assert "'plugin_test_awf_mw'" in proc.stdout
+    assert "'plugin_test_awf_mw_2'" in proc.stdout
+
+
+def test_plugin_system_multiple_plugins(session):
+    config_plugins = loadfixture("workspacebuilder/plugin_multiple_plugins.yaml")
+
+    sconfig = kaptan.Kaptan(handler='yaml')
+    sconfig = sconfig.import_config(config_plugins).get()
+    sconfig = config.expand(sconfig)
+
+    builder = WorkspaceBuilder(sconf=sconfig, plugins=load_plugins(sconfig))
+    assert len(builder.plugins) > 0
+
+    builder.build(session=session)
+
+    # Drop through to the before_script plugin hook
+    proc = session.cmd('display-message', '-p', "'#S'")
+    assert proc.stdout[0] == "'plugin_test_bwb'"
+
+    # Drop through to the after_window_finished. This won't succeed
+    # unless on_window_create succeeds because of how the test plugin
+    # override methods are currently written
+    proc = session.cmd('display-message', '-p', "'#W'")
+    assert proc.stdout[0] == "'mp_test_awf'"
diff --git a/tmuxp/__about__.py b/tmuxp/__about__.py
index 7fe395812e9..7242004d0b6 100644
--- a/tmuxp/__about__.py
+++ b/tmuxp/__about__.py
@@ -1,6 +1,6 @@
 __title__ = 'tmuxp'
 __package_name__ = 'tmuxp'
-__version__ = '1.6.1'
+__version__ = '1.7.0a1'
 __description__ = 'tmux session manager'
 __email__ = 'tony@git-pull.com'
 __author__ = 'Tony Narlock'
diff --git a/tmuxp/cli.py b/tmuxp/cli.py
index 6b1ac0cf5df..dc0b93571f7 100644
--- a/tmuxp/cli.py
+++ b/tmuxp/cli.py
@@ -7,6 +7,7 @@
 """
 from __future__ import absolute_import
 
+import importlib
 import logging
 import os
 import sys
@@ -372,13 +373,48 @@ def scan_config(config, config_dir=None):
     return config
 
 
-def _reattach(session):
+def load_plugins(sconf):
+    """
+    Load and return plugins in config
+    """
+    plugins = []
+    if 'plugins' in sconf:
+        for plugin in sconf['plugins']:
+            try:
+                module_name = plugin.split('.')
+                module_name = '.'.join(module_name[:-1])
+                plugin_name = plugin.split('.')[-1]
+                plugin = getattr(importlib.import_module(module_name), plugin_name)
+                plugins.append(plugin())
+            except exc.TmuxpPluginException as error:
+                if not click.confirm(
+                    '%sSkip loading %s?'
+                    % (click.style(str(error), fg='yellow'), plugin_name),
+                    default=True,
+                ):
+                    click.echo(
+                        click.style('[Not Skipping] ', fg='yellow')
+                        + 'Plugin versions constraint not met. Exiting...'
+                    )
+                    sys.exit(1)
+            except Exception as error:
+                click.echo(
+                    click.style('[Plugin Error] ', fg='red')
+                    + "Couldn\'t load {0}\n".format(plugin)
+                    + click.style('{0}'.format(error), fg='yellow')
+                )
+                sys.exit(1)
+
+    return plugins
+
+
+def _reattach(builder):
     """
     Reattach session (depending on env being inside tmux already or not)
 
     Parameters
     ----------
-    session : :class:`libtmux.Session`
+    builder: :class:`workspacebuilder.WorkspaceBuilder`
 
     Notes
     -----
@@ -388,11 +424,18 @@ def _reattach(session):
 
     If not, ``tmux attach-session`` loads the client to the target session.
     """
+
+    for plugin in builder.plugins:
+        plugin.reattach(builder.session)
+        proc = builder.session.cmd('display-message', '-p', "'#S'")
+        for line in proc.stdout:
+            print(line)
+
     if 'TMUX' in os.environ:
-        session.switch_client()
+        builder.session.switch_client()
 
     else:
-        session.attach_session()
+        builder.session.attach_session()
 
 
 def load_workspace(
@@ -514,7 +557,9 @@ def load_workspace(
     which('tmux')  # raise exception if tmux not found
 
     try:  # load WorkspaceBuilder object for tmuxp config / tmux server
-        builder = WorkspaceBuilder(sconf=sconfig, server=t)
+        builder = WorkspaceBuilder(
+            sconf=sconfig, plugins=load_plugins(sconfig), server=t
+        )
     except exc.EmptyConfigException:
         click.echo('%s is empty or parsed no config data' % config_file, err=True)
         return
@@ -532,7 +577,7 @@ def load_workspace(
                 default=True,
             )
         ):
-            _reattach(builder.session)
+            _reattach(builder)
         return
 
     try:
@@ -590,13 +635,14 @@ def load_workspace(
             builder.session.kill_session()
             click.echo('Session killed.')
         elif choice == 'a':
-            if 'TMUX' in os.environ:
-                builder.session.switch_client()
-            else:
-                builder.session.attach_session()
+            _reattach(builder)
         else:
             sys.exit()
 
+    # Runs after before_script
+    for plugin in builder.plugins:
+        plugin.before_script(builder.session)
+
     return builder.session
 
 
diff --git a/tmuxp/config.py b/tmuxp/config.py
index bea1df00811..eee39ce45c4 100644
--- a/tmuxp/config.py
+++ b/tmuxp/config.py
@@ -42,6 +42,10 @@ def validate_schema(sconf):
         if 'window_name' not in window:
             raise exc.ConfigError('config window is missing "window_name"')
 
+    if 'plugins' in sconf:
+        if not isinstance(sconf['plugins'], list):
+            raise exc.ConfigError('"plugins" only supports list type')
+
     return True
 
 
diff --git a/tmuxp/exc.py b/tmuxp/exc.py
index fcf567796ff..fb847f82c1d 100644
--- a/tmuxp/exc.py
+++ b/tmuxp/exc.py
@@ -15,6 +15,8 @@ class TmuxpException(Exception):
 
     """Base Exception for Tmuxp Errors."""
 
+    pass
+
 
 class ConfigError(TmuxpException):
 
@@ -30,6 +32,13 @@ class EmptyConfigException(ConfigError):
     pass
 
 
+class TmuxpPluginException(TmuxpException):
+
+    """Base Exception for Tmuxp Errors."""
+
+    pass
+
+
 class BeforeLoadScriptNotExists(OSError):
     def __init__(self, *args, **kwargs):
         super(BeforeLoadScriptNotExists, self).__init__(*args, **kwargs)
diff --git a/tmuxp/plugin.py b/tmuxp/plugin.py
new file mode 100644
index 00000000000..759e0bb4714
--- /dev/null
+++ b/tmuxp/plugin.py
@@ -0,0 +1,227 @@
+from distutils.version import LooseVersion
+
+import libtmux
+from libtmux.common import get_version
+
+from .__about__ import __version__
+from .exc import TmuxpPluginException
+
+#: Minimum version of tmux required to run libtmux
+TMUX_MIN_VERSION = '1.8'
+
+#: Most recent version of tmux supported
+TMUX_MAX_VERSION = None
+
+#: Minimum version of libtmux required to run libtmux
+LIBTMUX_MIN_VERSION = '0.8.3'
+
+#: Most recent version of libtmux supported
+LIBTMUX_MAX_VERSION = None
+
+#: Minimum version of tmuxp required to use plugins
+TMUXP_MIN_VERSION = '1.6.0'
+
+#: Most recent version of tmuxp
+TMUXP_MAX_VERSION = None
+
+
+class TmuxpPlugin:
+    def __init__(
+        self,
+        plugin_name='tmuxp-plugin',
+        tmux_min_version=TMUX_MIN_VERSION,
+        tmux_max_version=TMUX_MAX_VERSION,
+        tmux_version_incompatible=None,
+        libtmux_min_version=LIBTMUX_MIN_VERSION,
+        libtmux_max_version=LIBTMUX_MAX_VERSION,
+        libtmux_version_incompatible=None,
+        tmuxp_min_version=TMUXP_MIN_VERSION,
+        tmuxp_max_version=TMUXP_MAX_VERSION,
+        tmuxp_version_incompatible=None,
+    ):
+        """
+        Initialize plugin.
+
+        The default version values are set to the versions that the plugin
+        system requires.
+
+        Parameters
+        ----------
+        plugin_name : str
+            Name of the child plugin. Used in error message plugin fails to
+            load
+
+        tmux_min_version : str
+            Min version of tmux that the plugin supports
+
+        tmux_max_version : str
+            Min version of tmux that the plugin supports
+
+        tmux_version_incompatible : list
+            Versions of tmux that are incompatible with the plugin
+
+        libtmux_min_version : str
+            Min version of libtmux that the plugin supports
+
+        libtmux_max_version : str
+            Max version of libtmux that the plugin supports
+
+        libtmux_version_incompatible : list
+            Versions of libtmux that are incompatible with the plugin
+
+        tmuxp_min_version : str
+            Min version of tmuxp that the plugin supports
+
+        tmuxp_max_version : str
+            Max version of tmuxp that the plugin supports
+
+        tmuxp_version_incompatible : list
+            Versions of tmuxp that are incompatible with the plugin
+
+        """
+        self.plugin_name = plugin_name
+
+        # Dependency versions
+        self.tmux_version = get_version()
+        self.libtmux_version = libtmux.__version__
+        self.tmuxp_version = LooseVersion(__version__)
+
+        self.version_constraints = {
+            'tmux': {
+                'version': self.tmux_version,
+                'vmin': tmux_min_version,
+                'vmax': tmux_max_version,
+                'incompatible': tmux_version_incompatible
+                if tmux_version_incompatible
+                else [],
+            },
+            'libtmux': {
+                'version': self.libtmux_version,
+                'vmin': libtmux_min_version,
+                'vmax': libtmux_max_version,
+                'incompatible': libtmux_version_incompatible
+                if libtmux_version_incompatible
+                else [],
+            },
+            'tmuxp': {
+                'version': self.tmuxp_version,
+                'vmin': tmuxp_min_version,
+                'vmax': tmuxp_max_version,
+                'incompatible': tmuxp_version_incompatible
+                if tmuxp_version_incompatible
+                else [],
+            },
+        }
+
+        self._version_check()
+
+    def _version_check(self):
+        """
+        Check all dependency versions for compatibility.
+        """
+        for dep, constraints in self.version_constraints.items():
+            try:
+                assert self._pass_version_check(**constraints)
+            except AssertionError:
+                raise TmuxpPluginException(
+                    'Incompatible {dep} version: {version}\n{plugin_name} '
+                    'requirements:\nmin: {vmin} | max: {vmax} | '
+                    'incompatible: {incompatible}\n'.format(
+                        dep=dep, plugin_name=self.plugin_name, **constraints
+                    )
+                )
+
+    def _pass_version_check(self, version, vmin, vmax, incompatible):
+        """
+        Provide affirmative if version compatibility is correct.
+        """
+        if vmin and version < LooseVersion(vmin):
+            return False
+        if vmax and version > LooseVersion(vmax):
+            return False
+        if version in incompatible:
+            return False
+
+        return True
+
+    def before_workspace_builder(self, session):
+        """
+        Provide a session hook previous to creating the workspace.
+
+        This runs after the session has been created but before any of
+        the windows/panes/commands are entered.
+
+        Parameters
+        ----------
+        session : :class:`libtmux.Session`
+            session to hook into
+        """
+        pass
+
+    def on_window_create(self, window):
+        """
+        Provide a window hook previous to doing anything with a window.
+
+        This runs runs before anything is created in the windows, like panes.
+
+        Parameters
+        ----------
+        window: :class:`libtmux.Window`
+            window to hook into
+        """
+        pass
+
+    def after_window_finished(self, window):
+        """
+        Provide a window hook after creating the window.
+
+        This runs after everything has been created in the window, including
+        the panes and all of the commands for the panes. It also runs after the
+        ``options_after`` has been applied to the window.
+
+        Parameters
+        ----------
+        window: :class:`libtmux.Window`
+            window to hook into
+        """
+        pass
+
+    def before_script(self, session):
+        """
+        Provide a session hook after the workspace has been built.
+
+        This runs after the workspace has been loaded with ``tmuxp load``. It
+        augments instead of replaces the ``before_script`` section of the
+        configuration.
+
+        This hook provides access to the LibTmux.session object for any
+        behavior that would be used in the ``before_script`` section of the
+        configuration file that needs access directly to the session object.
+        This runs after the workspace has been loaded with ``tmuxp load``.
+
+        The hook augments, rather than replaces, the ``before_script`` section
+        of the configuration. While it is possible to do all of the
+        ``before_script`` configuration in this function, if a shell script
+        is currently being used for the configuration, it would be cleaner to
+        continue using the script in the ``before_section``.
+
+        If changes to the session need to be made prior to
+        anything being built, please use ``before_workspace_builder`` instead.
+
+        Parameters
+        ----------
+        session : :class:`libtmux.Session`
+            session to hook into
+        """
+        pass
+
+    def reattach(self, session):
+        """
+        Provide a session hook before reattaching to the session.
+
+        Parameters
+        ----------
+        session : :class:`libtmux.Session`
+            session to hook into
+        """
+        pass
diff --git a/tmuxp/workspacebuilder.py b/tmuxp/workspacebuilder.py
index d24164f5f9e..d313438d83e 100644
--- a/tmuxp/workspacebuilder.py
+++ b/tmuxp/workspacebuilder.py
@@ -68,7 +68,7 @@ class WorkspaceBuilder(object):
     a session inside tmux (when `$TMUX` is in the env variables).
     """
 
-    def __init__(self, sconf, server=None):
+    def __init__(self, sconf, plugins=[], server=None):
         """
         Initialize workspace loading.
 
@@ -77,6 +77,9 @@ def __init__(self, sconf, server=None):
         sconf : dict
             session config, includes a :py:obj:`list` of ``windows``.
 
+        plugins : list
+            plugins to be used for this session
+
         server : :class:`libtmux.Server`
             tmux server to build session in
 
@@ -98,6 +101,8 @@ def __init__(self, sconf, server=None):
 
         self.sconf = sconf
 
+        self.plugins = plugins
+
     def session_exists(self, session_name=None):
         exists = self.server.has_session(session_name)
         if not exists:
@@ -159,6 +164,9 @@ def build(self, session=None):
 
         assert isinstance(session, Session)
 
+        for plugin in self.plugins:
+            plugin.before_workspace_builder(self.session)
+
         focus = None
 
         if 'before_script' in self.sconf:
@@ -186,6 +194,9 @@ def build(self, session=None):
         for w, wconf in self.iter_create_windows(session):
             assert isinstance(w, Window)
 
+            for plugin in self.plugins:
+                plugin.on_window_create(w)
+
             focus_pane = None
             for p, pconf in self.iter_create_panes(w, wconf):
                 assert isinstance(p, Pane)
@@ -202,6 +213,9 @@ def build(self, session=None):
 
             self.config_after_window(w, wconf)
 
+            for plugin in self.plugins:
+                plugin.after_window_finished(w)
+
             if focus_pane:
                 focus_pane.select_pane()