diff --git a/jerry-core/jerry-extension.h b/jerry-core/jerry-extension.h
index 779530a50..186e40674 100644
--- a/jerry-core/jerry-extension.h
+++ b/jerry-core/jerry-extension.h
@@ -53,6 +53,11 @@ typedef struct
   };
 } jerry_extension_field_t;
 
+/**
+ * Forward declare to make compiler happy
+ */
+struct jerry_extension_function_t;
+
 /**
  * Pointer to extension function implementation
  */