diff --git a/pkgs/development/python-modules/expiringdict/default.nix b/pkgs/development/python-modules/expiringdict/default.nix
index 6478de1aff92d..4fc3366a7a42a 100644
--- a/pkgs/development/python-modules/expiringdict/default.nix
+++ b/pkgs/development/python-modules/expiringdict/default.nix
@@ -28,6 +28,12 @@ buildPythonPackage rec {
       url = "https://github.com/mailgun/expiringdict/commit/1c0f82232d20f8b3b31c9269a4d0e9510c1721a6.patch";
       hash = "sha256-IeeJVb2tOwRhEPNGqM30fNZyz3jFcnZNWC3I6K1+hSY=";
     })
+
+    # apply mailgun/expiringdict#56 for compatibility with Python 3.12
+    (fetchpatch2 {
+      url = "https://github.com/mailgun/expiringdict/commit/976faf3664d54049e443aca054f5819db834577b.patch";
+      hash = "sha256-FNdnU6iUMyED5j8oAjhmJTR7zQeEc/Z5s64pdeT4F8w=";
+    })
   ];
 
   nativeCheckInputs = [