diff --git a/Lib/enum.py b/Lib/enum.py
index eaa517e2fbc39b..c87aeef715761a 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -771,10 +771,15 @@ def __contains__(cls, value):
         `value` is in `cls` if:
         1) `value` is a member of `cls`, or
         2) `value` is the value of one of the `cls`'s members.
+        3) `value` is a pseudo-member (flags)
         """
         if isinstance(value, cls):
             return True
-        return value in cls._value2member_map_ or value in cls._unhashable_values_
+        try:
+            cls(value)
+            return True
+        except ValueError:
+            return value in cls._unhashable_values_
 
     def __delattr__(cls, attr):
         # nicer error message when someone tries to delete an attribute
diff --git a/Lib/test/test_enum.py b/Lib/test/test_enum.py
index 2e50ae0fe96586..a606002ffe958b 100644
--- a/Lib/test/test_enum.py
+++ b/Lib/test/test_enum.py
@@ -422,6 +422,7 @@ def test_basics(self):
             self.assertEqual(str(TE), "<flag 'MainEnum'>")
             self.assertEqual(format(TE), "<flag 'MainEnum'>")
             self.assertTrue(TE(5) is self.dupe2)
+            self.assertTrue(7 in TE)
         else:
             self.assertEqual(repr(TE), "<enum 'MainEnum'>")
             self.assertEqual(str(TE), "<enum 'MainEnum'>")
@@ -4848,6 +4849,7 @@ class Color(enum.Enum)
  |      `value` is in `cls` if:
  |      1) `value` is a member of `cls`, or
  |      2) `value` is the value of one of the `cls`'s members.
+ |      3) `value` is a pseudo-member (flags)
  |
  |  __getitem__(name)
  |      Return the member matching `name`.
diff --git a/Misc/NEWS.d/next/Library/2025-03-10-12-26-56.gh-issue-131045.s1TssJ.rst b/Misc/NEWS.d/next/Library/2025-03-10-12-26-56.gh-issue-131045.s1TssJ.rst
new file mode 100644
index 00000000000000..b6aa07276bb546
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-03-10-12-26-56.gh-issue-131045.s1TssJ.rst
@@ -0,0 +1 @@
+Fix issue with ``__contains__``, values, and pseudo-members for :class:`enum.Flag`.