diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d16e9904..cb62fb6d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Added CI schedule variables endpoints
 * Added support for triggering a pipeline
+* Added support for the search_namespaces projects parameter
 
 [11.1.0]: https://github.com/GitLabPHP/Client/compare/11.0.0...11.1.0
 
diff --git a/src/Api/Projects.php b/src/Api/Projects.php
index d8c573963..61f05e27e 100644
--- a/src/Api/Projects.php
+++ b/src/Api/Projects.php
@@ -30,6 +30,7 @@ class Projects extends AbstractApi
      *                                              or last_activity_at fields (default is created_at)
      *     @var string $sort                        Return projects sorted in asc or desc order (default is desc)
      *     @var string $search                      return list of projects matching the search criteria
+     *     @var bool   $search_namespaces           Include ancestor namespaces when matching search criteria
      *     @var bool   $simple                      return only the ID, URL, name, and path of each project
      *     @var bool   $owned                       limit by projects owned by the current user
      *     @var bool   $membership                  limit by projects that the current user is a member of
@@ -66,6 +67,10 @@ public function all(array $parameters = [])
             ->setAllowedValues('sort', ['asc', 'desc'])
         ;
         $resolver->setDefined('search');
+        $resolver->setDefined('search_namespaces')
+            ->setAllowedTypes('search_namespaces', 'bool')
+            ->setNormalizer('search_namespaces', $booleanNormalizer)
+        ;
         $resolver->setDefined('simple')
             ->setAllowedTypes('simple', 'bool')
             ->setNormalizer('simple', $booleanNormalizer)
diff --git a/tests/Api/ProjectsTest.php b/tests/Api/ProjectsTest.php
index 3c21766a1..2e53efb66 100644
--- a/tests/Api/ProjectsTest.php
+++ b/tests/Api/ProjectsTest.php
@@ -125,6 +125,17 @@ public function shouldSearchProjects(): void
         $this->assertEquals($expectedArray, $api->all(['search' => 'a project']));
     }
 
+    /**
+     * @test
+     */
+    public function shouldSearchProjectsWithNamespace(): void
+    {
+        $expectedArray = $this->getMultipleProjectsDataWithNamespace();
+
+        $api = $this->getMultipleProjectsRequestMock('projects', $expectedArray, ['search' => 'a_project', 'search_namespaces' => 'true']);
+        $this->assertEquals($expectedArray, $api->all(['search' => 'a_project', 'search_namespaces' => true]));
+    }
+
     /**
      * @test
      */
@@ -1914,6 +1925,14 @@ protected function getMultipleProjectsData()
         ];
     }
 
+    protected function getMultipleProjectsDataWithNamespace()
+    {
+        return [
+            ['id' => 1, 'name' => 'A project', 'namespace' => ['id' => 4, 'name' => 'A namespace', 'path' => 'a_namespace']],
+            ['id' => 2, 'name' => 'Another project', 'namespace' => ['id' => 5, 'name' => 'Another namespace', 'path' => 'another_namespace']],
+        ];
+    }
+
     public function possibleAccessLevels()
     {
         return [