diff --git a/CHANGES b/CHANGES
index 64410011e3a..21824440daa 100644
--- a/CHANGES
+++ b/CHANGES
@@ -55,6 +55,8 @@ Bugs fixed
   undocumented
 * #9185: autodoc: typehints for overloaded functions and methods are inaccurate
 * #9250: autodoc: The inherited method not having docstring is wrongly parsed
+* #9250: autodoc: :confval:`autodoc_inherited_docstrings` does not effect to the
+  docstring of classes
 * #9217: manpage: The name of manpage directory that is generated by
   :confval:`man_make_section_directory` is not correct
 * #9224: ``:param:`` and ``:type:`` fields does not support a type containing
diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index ec1472e202c..fb02484e8ea 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -31,8 +31,8 @@
 from sphinx.pycode import ModuleAnalyzer, PycodeError
 from sphinx.util import inspect, logging
 from sphinx.util.docstrings import prepare_docstring, separate_metadata
-from sphinx.util.inspect import (evaluate_signature, getdoc, object_description, safe_getattr,
-                                 stringify_signature)
+from sphinx.util.inspect import (evaluate_signature, getclassdoc, getdoc, object_description,
+                                 safe_getattr, stringify_signature)
 from sphinx.util.typing import OptionSpec, get_type_hints, restify
 from sphinx.util.typing import stringify as stringify_typehint
 
@@ -1694,9 +1694,9 @@ def get_doc(self, ignore: int = None) -> Optional[List[List[str]]]:
         classdoc_from = self.options.get('class-doc-from', self.config.autoclass_content)
 
         docstrings = []
-        attrdocstring = self.get_attr(self.object, '__doc__', None)
-        if attrdocstring:
-            docstrings.append(attrdocstring)
+        classdocstring = getclassdoc(self.object, self.config.autodoc_inherit_docstrings)
+        if classdocstring:
+            docstrings.append(classdocstring)
 
         # for classes, what the "docstring" is can be controlled via a
         # config value; the default is only the class docstring
diff --git a/sphinx/ext/autodoc/mock.py b/sphinx/ext/autodoc/mock.py
index b562f47fd71..34e0960de20 100644
--- a/sphinx/ext/autodoc/mock.py
+++ b/sphinx/ext/autodoc/mock.py
@@ -165,10 +165,18 @@ def ismock(subject: Any) -> bool:
     if isinstance(subject, _MockModule):
         return True
 
+    try:
+        # check the object is a mock class
+        __mro__ = safe_getattr(subject, '__mro__', [])
+        if len(__mro__) > 2 and __mro__[1] is _MockObject:
+            return True
+    except AttributeError:
+        pass
+
     try:
         # check the object is mocked object
         __mro__ = safe_getattr(type(subject), '__mro__', [])
-        if len(__mro__) > 2 and __mro__[1] is _MockObject:
+:       if len(__mro__) > 2 and __mro__[1] is _MockObject:
             return True
     except AttributeError:
         pass
diff --git a/sphinx/util/inspect.py b/sphinx/util/inspect.py
index a415a7074c8..0201cac93a6 100644
--- a/sphinx/util/inspect.py
+++ b/sphinx/util/inspect.py
@@ -824,6 +824,24 @@ def signature_from_ast(node: ast.FunctionDef, code: str = '') -> inspect.Signatu
     return inspect.Signature(params, return_annotation=return_annotation)
 
 
+def getclassdoc(obj: Type, allow_inherited: bool = False) -> Optional[str]:
+    """Get the docstring for the class."""
+    from sphinx.ext.autodoc.mock import ismock
+
+    if not allow_inherited:
+        return safe_getattr(obj, '__doc__', None)
+    else:
+        for basecls in getmro(obj)[:-1]:
+            if ismock(basecls):
+                break
+
+            doc = safe_getattr(basecls, '__doc__', None)
+            if doc is not None:
+                return doc
+
+        return None
+
+
 def getdoc(obj: Any, attrgetter: Callable = safe_getattr,
            allow_inherited: bool = False, cls: Any = None, name: str = None) -> str:
     """Get the docstring for the object.
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index 4c16886b3fc..aa9a7d7925a 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -2296,6 +2296,8 @@ def test_overload2(app):
         '              Baz(x: str, y: str)',
         '   :module: target.overload2',
         '',
+        '   docstring',
+        '',
     ]
 
 
diff --git a/tests/test_util_inspect.py b/tests/test_util_inspect.py
index de4ad92366b..6c51c550c83 100644
--- a/tests/test_util_inspect.py
+++ b/tests/test_util_inspect.py
@@ -671,6 +671,29 @@ def func1(a, b, c):
     assert inspect.unpartial(func3) is func1
 
 
+def test_getclassdoc():
+    class Foo:
+        """docstring"""
+
+    class Bar(Foo):
+        pass
+
+    assert inspect.getclassdoc(Foo) == "docstring"
+    assert inspect.getclassdoc(Bar) is None
+    assert inspect.getclassdoc(Bar, True) == "docstring"
+
+
+def test_getclassdoc_mocked():
+    from sphinx.ext.autodoc.mock import _MockModule
+
+    dummy = _MockModule('dummy')
+
+    class Foo(dummy.Dummy):  # type: ignore
+        pass
+
+    assert inspect.getclassdoc(Foo) is None
+
+
 def test_getdoc_inherited_decorated_method():
     class Foo:
         def meth(self):