diff --git a/scss/_input-group.scss b/scss/_input-group.scss
index 7e756fa016..c591954451 100644
--- a/scss/_input-group.scss
+++ b/scss/_input-group.scss
@@ -128,6 +128,7 @@
 // manipulation.
 
 .input-group-lg > .form-control,
+.input-group-lg > .custom-select,
 .input-group-lg > .input-group-prepend > .input-group-text,
 .input-group-lg > .input-group-append > .input-group-text,
 .input-group-lg > .input-group-prepend > .btn,
@@ -140,6 +141,7 @@
 }
 
 .input-group-sm > .form-control,
+.input-group-sm > .custom-select,
 .input-group-sm > .input-group-prepend > .input-group-text,
 .input-group-sm > .input-group-append > .input-group-text,
 .input-group-sm > .input-group-prepend > .btn,
@@ -151,6 +153,11 @@
   @include border-radius($input-border-radius-sm);
 }
 
+.input-group-lg > .custom-select,
+.input-group-sm > .custom-select {
+  padding-right: ($custom-select-padding-x + $custom-select-indicator-padding);
+}
+
 
 // Prepend and append rounded corners
 //