diff --git a/pkgs/applications/window-managers/i3/lock.nix b/pkgs/applications/window-managers/i3/lock.nix
index 2c0a481676ff..b8dffa259d76 100644
--- a/pkgs/applications/window-managers/i3/lock.nix
+++ b/pkgs/applications/window-managers/i3/lock.nix
@@ -25,6 +25,7 @@ stdenv.mkDerivation rec {
     '';
     homepage = "https://i3wm.org/i3lock/";
     maintainers = with maintainers; [ malyn domenkozar ];
+    mainProgram = "i3lock";
     license = licenses.bsd3;
     platforms = platforms.all;
   };