diff --git a/types/plotly.js/tsconfig.json b/types/plotly.js/tsconfig.json
index 94a19223ed..776f3e5a66 100644
--- a/types/plotly.js/tsconfig.json
+++ b/types/plotly.js/tsconfig.json
@@ -7,7 +7,7 @@
         ],
         "noImplicitAny": true,
         "noImplicitThis": true,
-        "strictNullChecks": false,
+        "strictNullChecks": true,
         "baseUrl": "../",
         "typeRoots": [
             "../"