diff --git a/CHANGES b/CHANGES
index aac8a8b35..d21c82a5e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -18,6 +18,7 @@ Bugs fixed
 
 * #6442: LaTeX: admonitions of :rst:dir:`note` type can get separated from
   immediately preceding section title by pagebreak
+* #6448: autodoc: crashed when autodocumenting classes with ``__slots__ = None``
 
 Testing
 --------
diff --git a/sphinx/ext/autodoc/importer.py b/sphinx/ext/autodoc/importer.py
index 37bdae8a9..0c6f47039 100644
--- a/sphinx/ext/autodoc/importer.py
+++ b/sphinx/ext/autodoc/importer.py
@@ -128,7 +128,7 @@ def get_object_members(subject, objpath, attrgetter, analyzer=None):
                 members[name] = Attribute(name, True, value)
 
     # members in __slots__
-    if isclass(subject) and hasattr(subject, '__slots__'):
+    if isclass(subject) and getattr(subject, '__slots__', None) is not None:
         from sphinx.ext.autodoc import SLOTSATTR
 
         for name in subject.__slots__: