diff --git a/kitty/border_fragment.glsl b/kitty/border_fragment.glsl
index 01832299d..b4f1330c5 100644
--- a/kitty/border_fragment.glsl
+++ b/kitty/border_fragment.glsl
@@ -4,5 +4,5 @@ in vec3 color;
 out vec4 final_color;
 
 void main() {
-    final_color = vec4(color, background_opacity);
+    final_color = vec4(color * background_opacity, background_opacity);
 }