diff --git a/types/wpapi/tsconfig.json b/types/wpapi/tsconfig.json
index c017072758..af7f0df782 100644
--- a/types/wpapi/tsconfig.json
+++ b/types/wpapi/tsconfig.json
@@ -6,6 +6,7 @@
         "noImplicitAny": true,
         "noImplicitThis": true,
         "strictNullChecks": true,
+        "strictFunctionTypes": true,
         "baseUrl": "../",
         "typeRoots": ["../"],
         "types": [],