diff --git a/CHANGES b/CHANGES
index b94531b73ff..701eff9d5fe 100644
--- a/CHANGES
+++ b/CHANGES
@@ -30,6 +30,7 @@ Bugs fixed
 * #9651: autodoc: return type field is not generated even if
   :confval:`autodoc_typehints_description_target` is set to "documented" when
   its info-field-list contains ``:returns:`` field
+* #9657: autodoc: The base class for a subclass of mocked object is incorrect
 * #9630: autosummary: Failed to build summary table if :confval:`primary_domain`
   is not 'py'
 * #9670: html: Fix download file with special characters
diff --git a/sphinx/ext/autodoc/mock.py b/sphinx/ext/autodoc/mock.py
index b562f47fd71..62f36da7956 100644
--- a/sphinx/ext/autodoc/mock.py
+++ b/sphinx/ext/autodoc/mock.py
@@ -26,6 +26,7 @@ class _MockObject:
     """Used by autodoc_mock_imports."""
 
     __display_name__ = '_MockObject'
+    __name__ = ''
     __sphinx_mock__ = True
     __sphinx_decorator_args__: Tuple[Any, ...] = ()
 
@@ -40,7 +41,7 @@ def __new__(cls, *args: Any, **kwargs: Any) -> Any:
         return super().__new__(cls)
 
     def __init__(self, *args: Any, **kwargs: Any) -> None:
-        self.__qualname__ = ''
+        self.__qualname__ = self.__name__
 
     def __len__(self) -> int:
         return 0
@@ -73,6 +74,7 @@ def _make_subclass(name: str, module: str, superclass: Any = _MockObject,
                    attributes: Any = None, decorator_args: Tuple = ()) -> Any:
     attrs = {'__module__': module,
              '__display_name__': module + '.' + name,
+             '__name__': name,
              '__sphinx_decorator_args__': decorator_args}
     attrs.update(attributes or {})
 
diff --git a/tests/test_util_typing.py b/tests/test_util_typing.py
index d493a004035..c34c4bebc8d 100644
--- a/tests/test_util_typing.py
+++ b/tests/test_util_typing.py
@@ -17,6 +17,7 @@
 
 import pytest
 
+from sphinx.ext.autodoc import mock
 from sphinx.util.typing import restify, stringify
 
 
@@ -170,6 +171,12 @@ def test_restify_broken_type_hints():
     assert restify(BrokenType) == ':py:class:`tests.test_util_typing.BrokenType`'
 
 
+def test_restify_mock():
+    with mock(['unknown']):
+        import unknown
+        assert restify(unknown.secret.Class) == ':py:class:`unknown.secret.Class`'
+
+
 def test_stringify():
     assert stringify(int) == "int"
     assert stringify(str) == "str"
@@ -294,3 +301,9 @@ def test_stringify_type_union_operator():
 
 def test_stringify_broken_type_hints():
     assert stringify(BrokenType) == 'tests.test_util_typing.BrokenType'
+
+
+def test_stringify_mock():
+    with mock(['unknown']):
+        import unknown
+        assert stringify(unknown.secret.Class) == 'unknown.secret.Class'