diff --git a/pkgs/development/python-modules/smtpdfix/default.nix b/pkgs/development/python-modules/smtpdfix/default.nix
index f9d7d2931e5a..5d34cd6693bf 100644
--- a/pkgs/development/python-modules/smtpdfix/default.nix
+++ b/pkgs/development/python-modules/smtpdfix/default.nix
@@ -1,6 +1,7 @@
 { lib
 , buildPythonPackage
 , fetchPypi
+, pythonAtLeast
 , setuptools
 , pytest
 , portpicker
@@ -36,6 +37,11 @@ buildPythonPackage rec {
     pytest-asyncio
   ];
 
+  disabledTests = lib.optionals (pythonAtLeast "3.12") [
+    # https://github.com/bebleo/smtpdfix/issues/335
+    "test_missing_certs"
+  ];
+
   meta = with lib; {
     description = "An SMTP server for use as a pytest fixture for testing";
     homepage = "https://github.com/bebleo/smtpdfix";