Who is and has been Secretary-General of the United Nations?

António Guterres is the current Secretary-General of the United Nations.

 He is the ninth Secretary-General, his term began 1 January 2017. 

The list of Secretaries-General, with the date of their term in office, is:

1. Trygve Lie, from Norway, 1946-1952
2. Dag Hammarskjöld, from Sweden, 1953-1961
3. U Thant, from Burma (now Myanmar), 1961-1971
4. Kurt Waldheim, from Austria, 1972-1981
5. Javier Perez de Cuellar, from Peru, 1982-1991
6. Boutros Boutros-Ghali, from Egypt, 1992-1996
7. Kofi A. Annan, from Ghana, 1997-2006
8. Ban Ki-moon, from Republic of Korea, 2007-2016
9. António Guterres, from Portugal, 2017-present

Gladwyn Jebb, from the United Kingdom, served as Acting Secretary-General from 24 October 1945 - 1 February 1946.

In late December 1950 and early 1951, Secretary-General Trygve Lie traveled to Europe to spend the holidays with his family. Following the holidays, he traveled to Geneva, Paris, and London in search of a venue for the 6th regular session of the General Assembly (eventually held in Paris). Before his departure, the Secretary-General appointed then Assistant Secretary-General for the Department of Economic and Social Affairs, Mr. David K. Owen, to perform as Acting Secretary-General during his absence from New York. (See press release SG/135 of 21 December 1950 for more details.)

The Research Guide on the Secretariat provides links to more information about the appointments and additional resources held by the Library for each Secretary-General.