diff --git a/pkgs/by-name/pr/prismlauncher-unwrapped/package.nix b/pkgs/by-name/pr/prismlauncher-unwrapped/package.nix
index 3e6f66e430a6..d05ab5abcb56 100644
--- a/pkgs/by-name/pr/prismlauncher-unwrapped/package.nix
+++ b/pkgs/by-name/pr/prismlauncher-unwrapped/package.nix
@@ -5,7 +5,7 @@
   cmake,
   cmark,
   extra-cmake-modules,
-  fetchpatch,
+  fetchpatch2,
   gamemode,
   ghc_filesystem,
   jdk17,
@@ -45,6 +45,16 @@ stdenv.mkDerivation (finalAttrs: {
     ln -s ${libnbtplusplus} source/libraries/libnbtplusplus
   '';
 
+  patches = [
+    # https://github.com/PrismLauncher/PrismLauncher/pull/3622
+    # https://github.com/NixOS/nixpkgs/issues/400119
+    (fetchpatch2 {
+      name = "fix-qt6.9-compatibility.patch";
+      url = "https://github.com/PrismLauncher/PrismLauncher/commit/8bb9b168fb996df9209e1e34be854235eda3d42a.diff";
+      hash = "sha256-hOqWBrUrVUhMir2cfc10gu1i8prdNxefTyr7lH6KA2c=";
+    })
+  ];
+
   nativeBuildInputs = [
     cmake
     ninja