diff --git a/dash/testing/browser.py b/dash/testing/browser.py
index c4fcb8fca8..8344d744f7 100644
--- a/dash/testing/browser.py
+++ b/dash/testing/browser.py
@@ -51,6 +51,7 @@ def __init__(
         percy_assets_root="",
         wait_timeout=10,
         pause=False,
+        driver=None,
     ):
         self._browser = browser.lower()
         self._remote_url = remote_url
@@ -65,7 +66,10 @@ def __init__(
         self._percy_run = percy_run
         self._pause = pause
 
-        self._driver = until(self.get_webdriver, timeout=1)
+        if driver:
+            self._driver = driver
+        else:
+            self._driver = until(self.get_webdriver, timeout=1)
         self._driver.implicitly_wait(2)
 
         self._wd_wait = WebDriverWait(self.driver, wait_timeout)