diff --git a/less/theme.less b/less/theme.less
index 3673accc09..6f2eb62126 100644
--- a/less/theme.less
+++ b/less/theme.less
@@ -52,6 +52,7 @@
     border-color: darken(@btn-color, 14%);
   }
 
+  &.disabled,
   &:disabled,
   &[disabled] {
     background-color: darken(@btn-color, 12%);