The UN Secretary-General is a concept and an office, serving as the chief administrative officer of the United Nations and the head of the UN Secretariat, one of the six principal organs of the UN. The role is also described as being "equal parts diplomat and advocate, civil servant, and CEO". The position was established with the founding of the UN in 1945, succeeding the Secretary-General of the League of Nations. The creation of the office aimed to provide an international civil service devoted to the organization's interests, a concept traceable to the first League of Nations Secretary-General, Sir Erik Drummond.
The mechanism of the office is primarily defined in Chapter XV (Articles 97 to 101) of the UN Charter. Article 97 states the Secretary-General is appointed by the General Assembly upon the recommendation of the Security Council. The most significant political power is granted by Article 99, which allows the Secretary-General to bring to the attention of the Security Council "any matter which in his opinion may threaten the maintenance of international peace and security". Furthermore, Article 100 mandates that the Secretary-General and staff must not seek or receive instructions from any government external to the UN, ensuring their exclusively international character. The Secretary-General serves a renewable term of five years.
The selection process has undergone recent changes to increase transparency and inclusivity, building on the landmark General Assembly resolution 69/321. This resolution, which influenced the selection of António Guterres in 2016, introduced public scrutiny and candidate hearings. The process was further refined by resolution 79/327, adopted in September 2025, which introduced more explicit rules, greater ethics oversight, and stronger visibility for the General Assembly. Despite these changes, the core mechanism remains the same: the Security Council recommends a candidate, which is subject to the veto of any of the five permanent members, and the General Assembly formally appoints the individual. The office connects directly to the UN Security Council and the UN General Assembly, as well as the Economic and Social Council and the Trusteeship Council, where the Secretary-General acts in an official capacity (Article 98).