diff --git a/less/dropdowns.less b/less/dropdowns.less
index e6bd18779b..5d7e0fb4e1 100644
--- a/less/dropdowns.less
+++ b/less/dropdowns.less
@@ -166,7 +166,7 @@
     // Firefox fix for https://github.com/twbs/bootstrap/issues/9538. Once this
     // gets fixed, restore `border-top: 0;`.
     border-top: 0 dotted;
-    border-bottom: 4px solid @dropdown-caret-color;
+    border-bottom: @caret-width-base solid @dropdown-caret-color;
     content: "";
   }
   // Different positioning for bottom up menu