Peter Martin Anker (21 March 1903 – 7 January 1977) was a Norwegian diplomat. He worked for the League of Nations, Red Cross and United Nations before, during and after the Second World War. He was then an ambassador in different European, Asian and African countries from 1951 to 1973. He was stationed in six different countries, but with side responsibilities for other countries, he was an ambassador in fifteen different countries during his career (with Austria counted twice).
He was a son of physician Peter Martin Anker (1872–1903) and Marie Reimers (1871–1958), a member of the Anker family. He was a great-grandson of Peter Martin Anker, grandson of Herman Anker, nephew of Katti Anker Møller (and her husband Kai Møller) and Ella Anker, grandnephew of Nils Anker, Christian August Anker and Dikka Møller, first cousin of Øyvind Anker, Synnøve Anker Aurdal and Tove Mohr, and uncle of Peter Martin Anker. In 1931 he married Harriet Celine Wedel Jarlsberg, a daughter of Peder Anker Wedel Jarlsberg and granddaughter of Einar Westye Egeberg.
He finished secondary education in 1921, took the law degree in 1926, and was hired in the Norwegian Ministry of Foreign Affairs in 1927. He was an attaché at the Norwegian legation in Paris before returning to Norway as a secretary in 1929. He worked for the League of Nations before World War II, being hired as a secretary in 1931. He was a secretary in the observatory commission in Alexandrette from 1936 to 1937, the later Hatay State.