Sir John Walter Nicholls GCMG OBE (4 October 1909 – 25 October 1970) was a British diplomat who was ambassador to Israel, Yugoslavia, Belgium and South Africa.

He joined the Foreign Office with the rank of third secretary in 1932.

[1] In 1939 he was seconded to the Ministry of Economic Warfare and was appointed OBE for his work there in the 1941 Birthday Honours.

[2] He was Commercial Counsellor in the British embassy at Lisbon 1943-1944, in the Control Commission for Austria 1944–46, Head of the Supply and Relief Department at the Foreign Office 1946-47, Head of German Trade/Commercial and Industry Department, at the Foreign Office 1947-49, Minister at Moscow 1949-51, Assistant Under-Secretary of State at the Foreign Office 1951–54, ambassador to Israel 1954–57, ambassador to Yugoslavia 1957–60, ambassador to Belgium 1960–63, Deputy Under-Secretary of State at the Foreign Office 1963–66,[3] and ambassador to South Africa 1966–69.

[4] Nicholls was appointed CMG in the 1948 Birthday Honours,[5] knighted KCMG in the 1956 New Year Honours[6] and raised to GCMG in the 1970 New Year Honours.