Ivor John Greenwood QC (15 November 1926 – 13 October 1976) was an Australian barrister and politician. He was a member of the Liberal Party and held senior ministerial office in the McMahon and Fraser governments. He served as Minister for Health (1971), Attorney-General (1971–1972, 1975) and Minister for the Environment, Housing and Community Development (1975–1976). He was a Senator for Victoria from 1968 until his death in 1976, aged 49.

Greenwood was born on 15 November 1926 in North Melbourne, Victoria. He was the oldest of three children born to Joy Olive (née Vickers) and Bartlett John Greenwood.^[1] His father was a boilermaker with the Victorian Railways. Greenwood attended Hartwell State School and Mont Albert Central State School before winning a scholarship to Scotch College.^[2] In 1945 he matriculated to the University of Melbourne, graduating Bachelor of Laws in 1949. He served as president of the Melbourne University Liberal Club and the Students' Representative Council. He subsequently worked as an associate to two High Court judges, Frank Kitto and Owen Dixon.^[2]

Greenwood was called to the Victorian Bar in 1951 and shared chambers with future High Court justice and governor-general Ninian Stephen for a period. He "soon established a reputation as a scholarly but practical barrister, working principally in the fields of commercial and local government law".^[1] Greenwood served as honorary secretary of the Law Council of Australia from 1963 to 1968.^[2] He was also involved with the Law Association for Asia and the Western Pacific (later known as LAWASIA). He was appointed Queen's Counsel in 1969, but according to the Australian Dictionary of Biography did not "achieve the material success that would have been his had he confined himself to the usual activities of a barrister".^[1]