diff --git a/system/Model.php b/system/Model.php
index 25b2b354b990..e53c0aae4bd1 100644
--- a/system/Model.php
+++ b/system/Model.php
@@ -79,6 +79,8 @@
  * @method $this selectMax(string $select = '', string $alias = '')
  * @method $this selectMin(string $select = '', string $alias = '')
  * @method $this selectSum(string $select = '', string $alias = '')
+ * @method $this when($condition, callable $callback, ?callable $defaultCallback = null)
+ * @method $this whenNot($condition, callable $callback, ?callable $defaultCallback = null)
  * @method $this where($key, $value = null, ?bool $escape = null)
  * @method $this whereIn(?string $key = null, $values = null, ?bool $escape = null)
  * @method $this whereNotIn(?string $key = null, $values = null, ?bool $escape = null)
diff --git a/tests/system/Models/WhenWhenNotModelTest.php b/tests/system/Models/WhenWhenNotModelTest.php
new file mode 100644
index 000000000000..9f19b9c52d41
--- /dev/null
+++ b/tests/system/Models/WhenWhenNotModelTest.php
@@ -0,0 +1,142 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Models;
+
+use Tests\Support\Models\SecondaryModel;
+
+/**
+ * @group DatabaseLive
+ *
+ * @internal
+ */
+final class WhenWhenNotModelTest extends LiveModelTestCase
+{
+    public function testWhenWithTrueCondition(): void
+    {
+        $secondaryData = [
+            [
+                'key'   => 'foo',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'bar',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'baz',
+                'value' => 'foobaz',
+            ],
+        ];
+        $filter = 'foobar';
+
+        $this->createModel(SecondaryModel::class)->insertBatch($secondaryData);
+
+        $result = $this->model->when($filter, static function ($query, $filter) {
+            $query->where('value', $filter);
+        })->find();
+
+        $this->assertCount(2, $result);
+        $this->assertSame('foo', $result[0]->key);
+        $this->assertSame('bar', $result[1]->key);
+    }
+
+    public function testWhenWithFalseConditionAndDefaultCallback(): void
+    {
+        $secondaryData = [
+            [
+                'key'   => 'foo',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'bar',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'baz',
+                'value' => 'foobaz',
+            ],
+        ];
+        $filter = '';
+
+        $this->createModel(SecondaryModel::class)->insertBatch($secondaryData);
+
+        $result = $this->model->when($filter, static function ($query, $filter) {
+            $query->where('value', $filter);
+        }, static function ($query) {
+            $query->where('value', 'foobar');
+        })->find();
+
+        $this->assertCount(2, $result);
+        $this->assertSame('foo', $result[0]->key);
+        $this->assertSame('bar', $result[1]->key);
+    }
+
+    public function testWhenNotWithFalseCondition(): void
+    {
+        $secondaryData = [
+            [
+                'key'   => 'foo',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'bar',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'baz',
+                'value' => 'foobaz',
+            ],
+        ];
+        $filter = '';
+
+        $this->createModel(SecondaryModel::class)->insertBatch($secondaryData);
+
+        $result = $this->model->whenNot($filter, static function ($query, $filter) {
+            $query->where('value !=', 'foobar');
+        })->find();
+
+        $this->assertCount(1, $result);
+        $this->assertSame('baz', $result[0]->key);
+        $this->assertSame('foobaz', $result[0]->value);
+    }
+
+    public function testWhenNotWithTrueConditionAndDefaultCallback(): void
+    {
+        $secondaryData = [
+            [
+                'key'   => 'foo',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'bar',
+                'value' => 'foobar',
+            ],
+            [
+                'key'   => 'baz',
+                'value' => 'foobaz',
+            ],
+        ];
+        $filter = 'foobar';
+
+        $this->createModel(SecondaryModel::class)->insertBatch($secondaryData);
+
+        $result = $this->model->whenNot($filter, static function ($query, $filter) {
+            $query->where('value !=', 'foobar');
+        }, static function ($query) {
+            $query->where('value', 'foobar');
+        })->find();
+
+        $this->assertCount(2, $result);
+        $this->assertSame('foo', $result[0]->key);
+        $this->assertSame('bar', $result[1]->key);
+    }
+}