diff --git a/types/multiplexjs/tsconfig.json b/types/multiplexjs/tsconfig.json
index bad1ec3652..a459c3fb35 100644
--- a/types/multiplexjs/tsconfig.json
+++ b/types/multiplexjs/tsconfig.json
@@ -5,7 +5,7 @@
             "es6"
         ],
         "noImplicitAny": true,
-        "noImplicitThis": false,
+        "noImplicitThis": true,
         "strictNullChecks": false,
         "strictFunctionTypes": true,
         "baseUrl": "../",
@@ -20,4 +20,4 @@
         "index.d.ts",
         "multiplexjs-tests.ts"
     ]
-}
\ No newline at end of file
+}