diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
index f18c5a7e24..c130a34285 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
@@ -950,7 +950,7 @@ static void generate_to_cpp(SourceGenerator& generator, ParameterType& parameter
                 bool may_be_null = !optional_default_value.has_value() || parameter.type->is_nullable() || optional_default_value.value() == "null";
 
                 // Required dictionary members cannot be null.
-                may_be_null &= !member.required;
+                may_be_null &= !member.required && !member.default_value.has_value();
 
                 if (member.type->is_string() && optional && may_be_null) {
                     dictionary_generator.append(R"~~~(