diff --git a/sphinx/ext/autodoc/importer.py b/sphinx/ext/autodoc/importer.py
index 133ce1439c9..52b07639af6 100644
--- a/sphinx/ext/autodoc/importer.py
+++ b/sphinx/ext/autodoc/importer.py
@@ -206,7 +206,10 @@ def get_object_members(subject: Any, objpath: List[str], attrgetter: Callable,
     if isclass(subject) and getattr(subject, '__slots__', None) is not None:
         from sphinx.ext.autodoc import SLOTSATTR
 
-        for name in subject.__slots__:
+        slots = subject.__slots__
+        if isinstance(slots, str):
+            slots = [slots]
+        for name in slots:
             members[name] = Attribute(name, True, SLOTSATTR)
 
     # other members
diff --git a/tests/roots/test-ext-autodoc/target/slots.py b/tests/roots/test-ext-autodoc/target/slots.py
index 44e7503205f..17e469caca7 100644
--- a/tests/roots/test-ext-autodoc/target/slots.py
+++ b/tests/roots/test-ext-autodoc/target/slots.py
@@ -2,6 +2,10 @@ class Foo:
     __slots__ = ['attr']
 
 
+class FooSingleString:
+    __slots__ = 'attr'
+
+
 class Bar:
     __slots__ = {'attr1': 'docstring of attr1',
                  'attr2': 'docstring of attr2',
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index 9cb54de5b06..c0676f23ff1 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -1205,6 +1205,14 @@ def test_slots(app):
         '   .. py:attribute:: Foo.attr',
         '      :module: target.slots',
         '',
+        '',
+        '.. py:class:: FooSingleString()',
+        '   :module: target.slots',
+        '',
+        '',
+        '   .. py:attribute:: FooSingleString.attr',
+        '      :module: target.slots',
+        '',
     ]