diff --git a/CHANGES b/CHANGES
index ad9d61eca2c..24e519b7d87 100644
--- a/CHANGES
+++ b/CHANGES
@@ -15,6 +15,7 @@ Deprecated
 Features added
 --------------
 
+* #10234: autosummary: Add "autosummary" CSS class to summary tables
 * #10125: extlinks: Improve suggestion message for a reference having title
 * #9494, #9456: html search: Add a config variable
   :confval:`html_show_search_summary` to enable/disable the search summaries
diff --git a/sphinx/ext/autosummary/__init__.py b/sphinx/ext/autosummary/__init__.py
index 964c0f532f1..74804df4af7 100644
--- a/sphinx/ext/autosummary/__init__.py
+++ b/sphinx/ext/autosummary/__init__.py
@@ -417,7 +417,7 @@ def get_table(self, items: List[Tuple[str, str, str, str]]) -> List[Node]:
         table_spec['spec'] = r'\X{1}{2}\X{1}{2}'
 
         table = autosummary_table('')
-        real_table = nodes.table('', classes=['longtable'])
+        real_table = nodes.table('', classes=['autosummary longtable'])
         table.append(real_table)
         group = nodes.tgroup('', cols=2)
         real_table.append(group)