diff --git a/types/ember-testing-helpers/tsconfig.json b/types/ember-testing-helpers/tsconfig.json
index 725957a948..18a8730def 100644
--- a/types/ember-testing-helpers/tsconfig.json
+++ b/types/ember-testing-helpers/tsconfig.json
@@ -6,7 +6,7 @@
             "dom"
         ],
         "noImplicitAny": true,
-        "noImplicitThis": false,
+        "noImplicitThis": true,
         "strictNullChecks": true,
         "strictFunctionTypes": true,
         "baseUrl": "../",
@@ -21,4 +21,4 @@
         "index.d.ts",
         "ember-testing-helpers-tests.ts"
     ]
-}
\ No newline at end of file
+}