diff --git a/Libraries/LibJS/Runtime/FunctionPrototype.cpp b/Libraries/LibJS/Runtime/FunctionPrototype.cpp
index 3d63513327e..84a784059e7 100644
--- a/Libraries/LibJS/Runtime/FunctionPrototype.cpp
+++ b/Libraries/LibJS/Runtime/FunctionPrototype.cpp
@@ -51,6 +51,7 @@ void FunctionPrototype::initialize(Interpreter& interpreter, GlobalObject& globa
     define_native_function("bind", bind, 1, attr);
     define_native_function("call", call, 1, attr);
     define_native_function("toString", to_string, 0, attr);
+    define_native_function(interpreter.well_known_symbol_has_instance(), symbol_has_instance, 1, 0);
     define_property("length", Value(0), Attribute::Configurable);
     define_property("name", js_string(heap(), ""), Attribute::Configurable);
 }
@@ -167,4 +168,15 @@ JS_DEFINE_NATIVE_FUNCTION(FunctionPrototype::to_string)
     return js_string(interpreter, function_source);
 }
 
+JS_DEFINE_NATIVE_FUNCTION(FunctionPrototype::symbol_has_instance)
+{
+    auto* this_object = interpreter.this_value(global_object).to_object(interpreter, global_object);
+    if (!this_object)
+        return {};
+    if (!this_object->is_function())
+        return interpreter.throw_exception<TypeError>(ErrorType::NotA, "Function");
+
+    return ordinary_has_instance(interpreter, interpreter.argument(0), this_object);
+}
+
 }
diff --git a/Libraries/LibJS/Runtime/FunctionPrototype.h b/Libraries/LibJS/Runtime/FunctionPrototype.h
index 5e744004ea1..809589778af 100644
--- a/Libraries/LibJS/Runtime/FunctionPrototype.h
+++ b/Libraries/LibJS/Runtime/FunctionPrototype.h
@@ -43,6 +43,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(bind);
     JS_DECLARE_NATIVE_FUNCTION(call);
     JS_DECLARE_NATIVE_FUNCTION(to_string);
+    JS_DECLARE_NATIVE_FUNCTION(symbol_has_instance);
 };
 
 }