The Office of Internal Oversight Services (OIOS) is the internal oversight body of the United Nations (UN).  The Office assists the Secretary-General in fulfilling his oversight responsibilities in respect of the resources and staff of the Organization through the provision of internal audit, investigation, inspection and evaluation services. 

The mandate of OIOS is derived from relevant General Assembly resolutions and decisions, including founding resolution 48/218 B of 29 July 1994.

The Office exercises operational independence under the authority of the Secretary-General in the conduct of its duties and, in accordance with Article 97 of the Charter, has the authority to initiate, carry out and report on any action which it considers necessary to fulfil its responsibilities. 

The OIOS vision is a strong and accountable United Nations, fortified by world-class internal oversight. Our mission is to deliver objective oversight results that make a difference.