diff --git a/sass/elements/form.sass b/sass/elements/form.sass
index 7d9f9bf7..c73f10fd 100644
--- a/sass/elements/form.sass
+++ b/sass/elements/form.sass
@@ -437,13 +437,13 @@ $help-size: $size-small !default
         .input,
         .select select
           border-radius: 0
-      &:first-child
+      &:first-child:not(:only-child)
         .button,
         .input,
         .select select
           border-bottom-right-radius: 0
           border-top-right-radius: 0
-      &:last-child
+      &:last-child:not(:only-child)
         .button,
         .input,
         .select select