diff --git a/pkgs/development/python-modules/demetriek/default.nix b/pkgs/development/python-modules/demetriek/default.nix
index b553a1b0837a..4d0f33a13873 100644
--- a/pkgs/development/python-modules/demetriek/default.nix
+++ b/pkgs/development/python-modules/demetriek/default.nix
@@ -5,6 +5,7 @@
 , buildPythonPackage
 , pydantic
 , fetchFromGitHub
+, fetchpatch
 , poetry-core
 , yarl
 , aresponses
@@ -27,6 +28,16 @@ buildPythonPackage rec {
     hash = "sha256-LCHHBcZgO9gw5jyaJiiS4lKyb0ut+PJvKTylIvIKHhc=";
   };
 
+  patches = [
+    # https://github.com/frenck/python-demetriek/pull/531
+    (fetchpatch {
+      name = "pydantic_2-compatibility.patch";
+      url = "https://github.com/frenck/python-demetriek/commit/e677fe5b735b6b28572e3e5fd6aab56fc056f5e6.patch";
+      excludes = [ "pyproject.toml" "poetry.lock" ];
+      hash = "sha256-oMVR45KHDhcPId/0X9obJXCPE8s1gk5IgsGsgZesdZw=";
+    })
+  ];
+
   postPatch = ''
     # Upstream doesn't set a version for the pyproject.toml
     substituteInPlace pyproject.toml \