diff --git a/types/moment-timezone/tsconfig.json b/types/moment-timezone/tsconfig.json
index 5b29fa3ff5..e0e0a7685b 100644
--- a/types/moment-timezone/tsconfig.json
+++ b/types/moment-timezone/tsconfig.json
@@ -6,7 +6,7 @@
         ],
         "noImplicitAny": true,
         "noImplicitThis": true,
-        "strictNullChecks": false,
+        "strictNullChecks": true,
         "strictFunctionTypes": true,
         "baseUrl": "../",
         "typeRoots": [