diff --git a/types/reactstrap/lib/FormGroup.d.ts b/types/reactstrap/lib/FormGroup.d.ts
index fd2390cdfa..c9293626cd 100644
--- a/types/reactstrap/lib/FormGroup.d.ts
+++ b/types/reactstrap/lib/FormGroup.d.ts
@@ -4,8 +4,8 @@ interface Props {
   disabled?: boolean;
   tag?: React.ReactType;
   color?: string;
-  className?: boolean;
+  className?: string;
 }
 
 declare var FormGroup: React.StatelessComponent<Props>;
-export default FormGroup;
\ No newline at end of file
+export default FormGroup;