United Nations Office of Internal Oversight Services

The United Nations Office of Internal Oversight Services (OIOS) is an independent office in the United Nations Secretariat whose mandate is to "assist the Secretary-General in fulfilling his internal oversight responsibilities in respect of the resources and staff of the Organization." Specifically, activities include internal audit, investigation, monitoring, evaluation, inspection, reporting and support services to the United Nations Secretariat.
Its intended and mandated function is similar to many national government audit organisations, like the Government Accountability Office in the United States. It reports not only to the General Assembly, but also to the Secretary-General.
The current head of the OIOS, Under-Secretary-General Fatoumata Ndiaye of Senegal, was appointed as Under-Secretary-General for Internal Oversight Services for a five-year term starting on 17 October 2019, succeeding Heidi Mendoza of the Philippines.