diff --git a/AK/Function.h b/AK/Function.h
index 4753c25e35..b0262e42ae 100644
--- a/AK/Function.h
+++ b/AK/Function.h
@@ -51,6 +51,8 @@ class Function<Out(In...)> {
     AK_MAKE_NONCOPYABLE(Function);
 
 public:
+    using ReturnType = Out;
+
     Function() = default;
     Function(std::nullptr_t)
     {