diff --git a/dtool/src/interrogate/interfaceMakerPythonSimple.cxx b/dtool/src/interrogate/interfaceMakerPythonSimple.cxx
index c0f1be390a..8a160216e8 100644
--- a/dtool/src/interrogate/interfaceMakerPythonSimple.cxx
+++ b/dtool/src/interrogate/interfaceMakerPythonSimple.cxx
@@ -98,7 +98,7 @@ write_module(ostream &out,ostream *out_h, InterrogateModuleDef *def) {
       << "#if PY_MAJOR_VERSION >= 3\n"
       << "static struct PyModuleDef python_simple_module = {\n"
       << "  PyModuleDef_HEAD_INIT,\n"
-      << "  \"" << def->library_name << "\",\n"
+      << "  \"" << def->module_name << "\",\n"
       << "  nullptr,\n"
       << "  -1,\n"
       << "  python_simple_funcs,\n"
diff --git a/dtool/src/interrogate/interrogate_module.cxx b/dtool/src/interrogate/interrogate_module.cxx
index 663e57762f..5b42d1db02 100644
--- a/dtool/src/interrogate/interrogate_module.cxx
+++ b/dtool/src/interrogate/interrogate_module.cxx
@@ -305,7 +305,7 @@ int write_python_table_native(std::ostream &out) {
       << "#if PY_MAJOR_VERSION >= 3\n"
       << "static struct PyModuleDef py_" << library_name << "_module = {\n"
       << "  PyModuleDef_HEAD_INIT,\n"
-      << "  \"" << library_name << "\",\n"
+      << "  \"" << module_name << "\",\n"
       << "  nullptr,\n"
       << "  -1,\n"
       << "  nullptr,\n"