Frederik Wilhelm Breitenstein (17 May 1933 Tampere – 6 June 2005 Helsinki) was a Finnish Permanent Representative to the United Nations in 1991–1998 and to the OSCE from 1983 to 1991.
He started his career at the United Nations in 1972 as a Council of Ministers.
In 1978, he was head of the Development Cooperation Department of the Ministry for Foreign Affairs.
After retiring, he served as adviser to the UN's "Food for Oil" program.