diff --git a/keystoneclient/tests/unit/v3/test_role_assignments.py b/keystoneclient/tests/unit/v3/test_role_assignments.py
index e77bdccce..21fc2c322 100644
--- a/keystoneclient/tests/unit/v3/test_role_assignments.py
+++ b/keystoneclient/tests/unit/v3/test_role_assignments.py
@@ -121,6 +121,22 @@ class RoleAssignmentsTests(utils.TestCase, utils.CrudTests):
         kwargs = {'scope.project.id': self.TEST_TENANT_ID}
         self.assertQueryStringContains(**kwargs)
 
+    def test_project_assignments_list_include_subtree(self):
+        ref_list = self.TEST_GROUP_PROJECT_LIST + self.TEST_USER_PROJECT_LIST
+        self.stub_entity('GET',
+                         [self.collection_key,
+                          '?scope.project.id=%s&include_subtree=True' %
+                          self.TEST_TENANT_ID],
+                         entity=ref_list)
+
+        returned_list = self.manager.list(project=self.TEST_TENANT_ID,
+                                          include_subtree=True)
+        self._assert_returned_list(ref_list, returned_list)
+
+        kwargs = {'scope.project.id': self.TEST_TENANT_ID,
+                  'include_subtree': 'True'}
+        self.assertQueryStringContains(**kwargs)
+
     def test_domain_assignments_list(self):
         ref_list = self.TEST_USER_DOMAIN_LIST
         self.stub_entity('GET',
diff --git a/keystoneclient/v3/role_assignments.py b/keystoneclient/v3/role_assignments.py
index d71f9eb11..fb9b5c71f 100644
--- a/keystoneclient/v3/role_assignments.py
+++ b/keystoneclient/v3/role_assignments.py
@@ -47,7 +47,8 @@ class RoleAssignmentManager(base.CrudManager):
             raise exceptions.ValidationError(msg)
 
     def list(self, user=None, group=None, project=None, domain=None, role=None,
-             effective=False, os_inherit_extension_inherited_to=None):
+             effective=False, os_inherit_extension_inherited_to=None,
+             include_subtree=False):
         """Lists role assignments.
 
         If no arguments are provided, all role assignments in the
@@ -69,6 +70,7 @@ class RoleAssignmentManager(base.CrudManager):
         :param string os_inherit_extension_inherited_to:
             return inherited role assignments for either 'projects' or
             'domains'. (optional)
+        :param boolean include_subtree: Include subtree (optional)
         """
 
         self._check_not_user_and_group(user, group)
@@ -90,6 +92,8 @@ class RoleAssignmentManager(base.CrudManager):
         if os_inherit_extension_inherited_to:
             query_params['scope.OS-INHERIT:inherited_to'] = (
                 os_inherit_extension_inherited_to)
+        if include_subtree:
+            query_params['include_subtree'] = include_subtree
 
         return super(RoleAssignmentManager, self).list(**query_params)