diff --git a/pkgs/development/python-modules/os-client-config/default.nix b/pkgs/development/python-modules/os-client-config/default.nix
index 9e64f72bd64f..21ac2f3c9fa7 100644
--- a/pkgs/development/python-modules/os-client-config/default.nix
+++ b/pkgs/development/python-modules/os-client-config/default.nix
@@ -1,6 +1,7 @@
 {
   lib,
   buildPythonPackage,
+  fetchpatch,
   fetchPypi,
   fixtures,
   jsonschema,
@@ -26,6 +27,14 @@ buildPythonPackage rec {
     hash = "sha256-4WomDy/VAK8U8Ve5t7fWkpLOg7D4pGHsaM5qikKWfL0=";
   };
 
+  patches = [
+    # Replace deprecated assertItemsEqual
+    (fetchpatch {
+      url = "https://github.com/openstack/os-client-config/commit/a72d8845545d6ac3b64b6fc48d0e2ada5750f6fe.patch";
+      hash = "sha256-i8DZCdpZ8yoN0WHseczycI4iwDP55Ibzo0KLy7Moy4M=";
+    })
+  ];
+
   build-system = [
     pbr
     setuptools