diff --git a/pkgs/applications/window-managers/i3/wmfocus.nix b/pkgs/applications/window-managers/i3/wmfocus.nix
index 1c06fc2ae28d..43a1c13ee0e5 100644
--- a/pkgs/applications/window-managers/i3/wmfocus.nix
+++ b/pkgs/applications/window-managers/i3/wmfocus.nix
@@ -1,5 +1,5 @@
 { lib, fetchFromGitHub, rustPlatform
-, xorg, python3, pkg-config, cairo, libxkbcommon }:
+, xorg, python3, pkg-config, cairo, expat, libxkbcommon }:
 
 rustPlatform.buildRustPackage rec {
   pname = "wmfocus";
@@ -15,7 +15,7 @@ rustPlatform.buildRustPackage rec {
   cargoHash = "sha256-4eoV/viI7Q7I7mIqcHVAyPf/y2RWaWX0B+mLZWMEbcI=";
 
   nativeBuildInputs = [ python3 pkg-config ];
-  buildInputs = [ cairo libxkbcommon xorg.xcbutilkeysyms ];
+  buildInputs = [ cairo expat libxkbcommon xorg.xcbutilkeysyms ];
 
   # For now, this is the only available featureset. This is also why the file is
   # in the i3 folder, even though it might be useful for more than just i3