diff --git a/pkgs/development/tools/open-policy-agent/default.nix b/pkgs/development/tools/open-policy-agent/default.nix
index 06161d95c4b2..891733635cce 100644
--- a/pkgs/development/tools/open-policy-agent/default.nix
+++ b/pkgs/development/tools/open-policy-agent/default.nix
@@ -2,6 +2,7 @@
 , stdenv
 , buildGoModule
 , fetchFromGitHub
+, fetchpatch
 , installShellFiles
 
 , enableWasmEval ? false
@@ -20,6 +21,15 @@ buildGoModule rec {
     hash = "sha256-fx7k6KvL0uy2NXLDLpCnN1ux9MGEO1CbX6TdLweVzag=";
   };
 
+  patches = [
+    # fix tests in 1.22.5
+    # https://github.com/open-policy-agent/opa/pull/6845
+    (fetchpatch {
+      url = "https://github.com/open-policy-agent/opa/commit/956358516c23b1f33f6667961e20aca65b91355b.patch";
+      hash = "sha256-1nfMwJwbYfdLg9j4ppP1IWdDeFq6vhXcDKr6uprP53U=";
+    })
+  ];
+
   vendorHash = null;
 
   nativeBuildInputs = [ installShellFiles ];