diff --git a/CHANGES b/CHANGES
index 52f00866b..b4dbf1ef7 100644
--- a/CHANGES
+++ b/CHANGES
@@ -79,6 +79,7 @@ Bugs fixed
 * #8522: autodoc:  ``__bool__`` method could be called
 * #8067: autodoc: A typehint for the instance variable having type_comment on
   super class is not displayed
+* #8545: autodoc: a __slots__ attribute is not documented even having docstring
 * #8477: autosummary: non utf-8 reST files are generated when template contains
   multibyte characters
 * #8501: autosummary: summary extraction splits text after "el at." unexpectedly
diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index 9ae115ef4..6ce0fbf9c 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -26,7 +26,8 @@ from sphinx.config import ENUM, Config
 from sphinx.deprecation import (RemovedInSphinx40Warning, RemovedInSphinx50Warning,
                                 RemovedInSphinx60Warning)
 from sphinx.environment import BuildEnvironment
-from sphinx.ext.autodoc.importer import get_module_members, get_object_members, import_object
+from sphinx.ext.autodoc.importer import (get_class_members, get_module_members,
+                                         get_object_members, import_object)
 from sphinx.ext.autodoc.mock import mock
 from sphinx.locale import _, __
 from sphinx.pycode import ModuleAnalyzer, PycodeError
@@ -274,9 +275,11 @@ class ObjectMember(tuple):
     def __new__(cls, name: str, obj: Any, **kwargs: Any) -> Any:
         return super().__new__(cls, (name, obj))  # type: ignore
 
-    def __init__(self, name: str, obj: Any, skipped: bool = False) -> None:
+    def __init__(self, name: str, obj: Any, docstring: Optional[str] = None,
+                 skipped: bool = False) -> None:
         self.__name__ = name
         self.object = obj
+        self.docstring = docstring
         self.skipped = skipped
 
 
@@ -708,6 +711,11 @@ class Documenter:
                 cls_doc = self.get_attr(cls, '__doc__', None)
                 if cls_doc == doc:
                     doc = None
+
+            if isinstance(obj, ObjectMember) and obj.docstring:
+                # hack for ClassDocumenter to inject docstring via ObjectMember
+                doc = obj.docstring
+
             has_doc = bool(doc)
 
             metadata = extract_metadata(doc)
@@ -1576,7 +1584,7 @@ class ClassDocumenter(DocstringSignatureMixin, ModuleLevelDocumenter):  # type:
                 self.add_line('   ' + _('Bases: %s') % ', '.join(bases), sourcename)
 
     def get_object_members(self, want_all: bool) -> Tuple[bool, ObjectMembers]:
-        members = get_object_members(self.object, self.objpath, self.get_attr, self.analyzer)
+        members = get_class_members(self.object, self.objpath, self.get_attr, self.analyzer)
         if not want_all:
             if not self.options.members:
                 return False, []  # type: ignore
@@ -1584,16 +1592,18 @@ class ClassDocumenter(DocstringSignatureMixin, ModuleLevelDocumenter):  # type:
             selected = []
             for name in self.options.members:  # type: str
                 if name in members:
-                    selected.append((name, members[name].value))
+                    selected.append(ObjectMember(name, members[name].value,
+                                                 docstring=members[name].docstring))
                 else:
                     logger.warning(__('missing attribute %s in object %s') %
                                    (name, self.fullname), type='autodoc')
             return False, selected
         elif self.options.inherited_members:
-            return False, [(m.name, m.value) for m in members.values()]
+            return False, [ObjectMember(m.name, m.value, docstring=m.docstring)
+                           for m in members.values()]
         else:
-            return False, [(m.name, m.value) for m in members.values()
-                           if m.directly_defined]
+            return False, [ObjectMember(m.name, m.value, docstring=m.docstring)
+                           for m in members.values() if m.class_ == self.object]
 
     def get_doc(self, encoding: str = None, ignore: int = None) -> List[List[str]]:
         if encoding is not None:
diff --git a/sphinx/ext/autodoc/importer.py b/sphinx/ext/autodoc/importer.py
index ec05a8a3d..d6e73d36a 100644
--- a/sphinx/ext/autodoc/importer.py
+++ b/sphinx/ext/autodoc/importer.py
@@ -241,6 +241,83 @@ def get_object_members(subject: Any, objpath: List[str], attrgetter: Callable,
     return members
 
 
+class ClassAttribute:
+    """The attribute of the class."""
+
+    def __init__(self, cls: Any, name: str, value: Any, docstring: Optional[str] = None):
+        self.class_ = cls
+        self.name = name
+        self.value = value
+        self.docstring = docstring
+
+
+def get_class_members(subject: Any, objpath: List[str], attrgetter: Callable,
+                      analyzer: ModuleAnalyzer = None) -> Dict[str, ClassAttribute]:
+    """Get members and attributes of target class."""
+    from sphinx.ext.autodoc import INSTANCEATTR
+
+    # the members directly defined in the class
+    obj_dict = attrgetter(subject, '__dict__', {})
+
+    members = {}  # type: Dict[str, ClassAttribute]
+
+    # enum members
+    if isenumclass(subject):
+        for name, value in subject.__members__.items():
+            if name not in members:
+                members[name] = ClassAttribute(subject, name, value)
+
+        superclass = subject.__mro__[1]
+        for name in obj_dict:
+            if name not in superclass.__dict__:
+                value = safe_getattr(subject, name)
+                members[name] = ClassAttribute(subject, name, value)
+
+    # members in __slots__
+    try:
+        __slots__ = getslots(subject)
+        if __slots__:
+            from sphinx.ext.autodoc import SLOTSATTR
+
+            for name, docstring in __slots__.items():
+                members[name] = ClassAttribute(subject, name, SLOTSATTR, docstring)
+    except (AttributeError, TypeError, ValueError):
+        pass
+
+    # other members
+    for name in dir(subject):
+        try:
+            value = attrgetter(subject, name)
+            unmangled = unmangle(subject, name)
+            if unmangled and unmangled not in members:
+                if name in obj_dict:
+                    members[unmangled] = ClassAttribute(subject, unmangled, value)
+                else:
+                    members[unmangled] = ClassAttribute(None, unmangled, value)
+        except AttributeError:
+            continue
+
+    # annotation only member (ex. attr: int)
+    for cls in getmro(subject):
+        try:
+            for name in getannotations(cls):
+                name = unmangle(cls, name)
+                if name and name not in members:
+                    members[name] = ClassAttribute(cls, name, INSTANCEATTR)
+        except AttributeError:
+            pass
+
+    if analyzer:
+        # append instance attributes (cf. self.attr1) if analyzer knows
+        namespace = '.'.join(objpath)
+        for (ns, name), docstring in analyzer.attr_docs.items():
+            if namespace == ns and name not in members:
+                members[name] = ClassAttribute(subject, name, INSTANCEATTR,
+                                               '\n'.join(docstring))
+
+    return members
+
+
 from sphinx.ext.autodoc.mock import (MockFinder, MockLoader, _MockModule, _MockObject,  # NOQA
                                      mock)
 
diff --git a/tests/roots/test-ext-autodoc/target/slots.py b/tests/roots/test-ext-autodoc/target/slots.py
index 144f97c95..32822fd38 100644
--- a/tests/roots/test-ext-autodoc/target/slots.py
+++ b/tests/roots/test-ext-autodoc/target/slots.py
@@ -1,8 +1,12 @@
 class Foo:
+    """docstring"""
+
     __slots__ = ['attr']
 
 
 class Bar:
+    """docstring"""
+
     __slots__ = {'attr1': 'docstring of attr1',
                  'attr2': 'docstring of attr2',
                  'attr3': None}
@@ -12,4 +16,6 @@ class Bar:
 
 
 class Baz:
+    """docstring"""
+
     __slots__ = 'attr'
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index a81a73b61..05b827c18 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -1172,6 +1172,8 @@ def test_slots(app):
         '.. py:class:: Bar()',
         '   :module: target.slots',
         '',
+        '   docstring',
+        '',
         '',
         '   .. py:attribute:: Bar.attr1',
         '      :module: target.slots',
@@ -1192,6 +1194,8 @@ def test_slots(app):
         '.. py:class:: Baz()',
         '   :module: target.slots',
         '',
+        '   docstring',
+        '',
         '',
         '   .. py:attribute:: Baz.attr',
         '      :module: target.slots',
@@ -1200,6 +1204,8 @@ def test_slots(app):
         '.. py:class:: Foo()',
         '   :module: target.slots',
         '',
+        '   docstring',
+        '',
         '',
         '   .. py:attribute:: Foo.attr',
         '      :module: target.slots',
diff --git a/tests/test_ext_autodoc_autoclass.py b/tests/test_ext_autodoc_autoclass.py
index 17c7f8944..c36305de3 100644
--- a/tests/test_ext_autodoc_autoclass.py
+++ b/tests/test_ext_autodoc_autoclass.py
@@ -77,6 +77,32 @@ def test_decorators(app):
     ]
 
 
+@pytest.mark.sphinx('html', testroot='ext-autodoc')
+def test_slots_attribute(app):
+    options = {"members": None}
+    actual = do_autodoc(app, 'class', 'target.slots.Bar', options)
+    assert list(actual) == [
+        '',
+        '.. py:class:: Bar()',
+        '   :module: target.slots',
+        '',
+        '   docstring',
+        '',
+        '',
+        '   .. py:attribute:: Bar.attr1',
+        '      :module: target.slots',
+        '',
+        '      docstring of attr1',
+        '',
+        '',
+        '   .. py:attribute:: Bar.attr2',
+        '      :module: target.slots',
+        '',
+        '      docstring of instance attr2',
+        '',
+    ]
+
+
 @pytest.mark.skipif(sys.version_info < (3, 7), reason='python 3.7+ is required.')
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_show_inheritance_for_subclass_of_generic_type(app):