diff --git a/gitlab/__init__.py b/gitlab/__init__.py
index b5f32c931..738085abd 100644
--- a/gitlab/__init__.py
+++ b/gitlab/__init__.py
@@ -642,8 +642,22 @@ def sanitized_url(url):
             return parsed._replace(path=new_path).geturl()
 
         url = self._build_url(path)
-        params = query_data.copy()
-        params.update(kwargs)
+
+        def copy_dict(dest, src):
+            for k, v in src.items():
+                if isinstance(v, dict):
+                    # Transform dict values in new attributes. For example:
+                    # custom_attributes: {'foo', 'bar'} =>
+                    #   custom_attributes['foo']: 'bar'
+                    for dict_k, dict_v in v.items():
+                        dest['%s[%s]' % (k, dict_k)] = dict_v
+                else:
+                    dest[k] = v
+
+        params = {}
+        copy_dict(params, query_data)
+        copy_dict(params, kwargs)
+
         opts = self._get_session_opts(content_type='application/json')
 
         # don't set the content-type header when uploading files
diff --git a/gitlab/v4/objects.py b/gitlab/v4/objects.py
index 106b10285..d7bb3d590 100644
--- a/gitlab/v4/objects.py
+++ b/gitlab/v4/objects.py
@@ -253,7 +253,7 @@ class UserManager(CRUDMixin, RESTManager):
     _obj_cls = User
 
     _list_filters = ('active', 'blocked', 'username', 'extern_uid', 'provider',
-                     'external', 'search')
+                     'external', 'search', 'custom_attributes')
     _create_attrs = (
         tuple(),
         ('email', 'username', 'name', 'password', 'reset_password', 'skype',
@@ -656,7 +656,7 @@ class GroupManager(CRUDMixin, RESTManager):
     _path = '/groups'
     _obj_cls = Group
     _list_filters = ('skip_groups', 'all_available', 'search', 'order_by',
-                     'sort', 'statistics', 'owned')
+                     'sort', 'statistics', 'owned', 'custom_attributes')
     _create_attrs = (
         ('name', 'path'),
         ('description', 'visibility', 'parent_id', 'lfs_enabled',
@@ -2639,7 +2639,8 @@ class ProjectManager(CRUDMixin, RESTManager):
     )
     _list_filters = ('search', 'owned', 'starred', 'archived', 'visibility',
                      'order_by', 'sort', 'simple', 'membership', 'statistics',
-                     'with_issues_enabled', 'with_merge_requests_enabled')
+                     'with_issues_enabled', 'with_merge_requests_enabled',
+                     'custom_attributes')
 
 
 class Runner(SaveMixin, ObjectDeleteMixin, RESTObject):
diff --git a/tools/python_test_v4.py b/tools/python_test_v4.py
index 4af9ea969..e06502018 100644
--- a/tools/python_test_v4.py
+++ b/tools/python_test_v4.py
@@ -129,6 +129,7 @@
 attrs = new_user.customattributes.list()
 assert(len(attrs) == 0)
 attr = new_user.customattributes.set('key', 'value1')
+assert(len(gl.users.list(custom_attributes={'key': 'value1'})) == 1)
 assert(attr.key == 'key')
 assert(attr.value == 'value1')
 assert(len(new_user.customattributes.list()) == 1)
@@ -234,6 +235,7 @@
 attrs = group2.customattributes.list()
 assert(len(attrs) == 0)
 attr = group2.customattributes.set('key', 'value1')
+assert(len(gl.groups.list(custom_attributes={'key': 'value1'})) == 1)
 assert(attr.key == 'key')
 assert(attr.value == 'value1')
 assert(len(group2.customattributes.list()) == 1)
@@ -303,6 +305,7 @@
 attrs = admin_project.customattributes.list()
 assert(len(attrs) == 0)
 attr = admin_project.customattributes.set('key', 'value1')
+assert(len(gl.projects.list(custom_attributes={'key': 'value1'})) == 1)
 assert(attr.key == 'key')
 assert(attr.value == 'value1')
 assert(len(admin_project.customattributes.list()) == 1)