diff --git a/modules/desktop/bspwm.nix b/modules/desktop/bspwm.nix
index 592055d8..c4fc0a01 100644
--- a/modules/desktop/bspwm.nix
+++ b/modules/desktop/bspwm.nix
@@ -60,6 +60,7 @@
       backend = "glx";
       vSync = true;
       inactiveOpacity = "0.90";
+      opacityRules = ["100:class_g = 'Firefox'"];
     };
   };