diff --git a/types/react-map-gl/index.d.ts b/types/react-map-gl/index.d.ts
index 2ae7ddbdf9..772e24081f 100644
--- a/types/react-map-gl/index.d.ts
+++ b/types/react-map-gl/index.d.ts
@@ -301,7 +301,7 @@ export class Popup extends BaseControl<PopupProps> {}
 export interface NavigationControlProps extends BaseControlProps {
     className?: string;
     onViewStateChange?: (info: ViewStateChangeInfo) => void;
-    onViewportChange: (viewport: ViewState) => void;
+    onViewportChange?: (viewport: ViewState) => void;
     showCompass?: boolean;
     showZoom?: boolean;
 }