diff --git a/nix/mkAtmApp.nix b/nix/mkAtmApp.nix
index 4efb848..5568794 100644
--- a/nix/mkAtmApp.nix
+++ b/nix/mkAtmApp.nix
@@ -45,7 +45,10 @@ pkgs.stdenv.mkDerivation (finalAttrs: {
     nodejs
     pnpm
     pkgs-unstable.pnpmConfigHook
-    pkgs.python3 # node-gyp (better-sqlite3)
+    # node-gyp@9.4.1 (pulled in by better-sqlite3) imports distutils, which
+    # Python 3.12 removed. pkgs.python3 became 3.12 in nixpkgs 24.11. Pin
+    # 3.11 here until pnpm-lock bumps better-sqlite3 to a node-gyp@10+ build.
+    pkgs.python311
     pkgs.pkg-config
     pkgs.autoPatchelfHook # patch .node ELF binaries
   ];