Sir William Macpherson of Cluny (born William Alan Macpherson on 1 April 1926 in Blairgowrie, Perth and Kinross) is a retired High Court judge, and the 27th Hereditary Chief of the Clan Macpherson. In the late 1990s, Macpherson led the public inquiry into the murder of Stephen Lawrence.
Macpherson was educated at Summer Fields School, a preparatory school near Oxford. He later studied at Wellington College in Crowthorne and Trinity College, Oxford. From 1944 to 1947, he served as a captain in the Scots Guards.
Macpherson was called to the bar in 1952.
From 1962 to 1965, he was a member of the Special Air Service within the Territorial Army, holding the ranks of commanding officer and, by 1965, lieutenant colonel. He was awarded the Territorial Efficiency Medal.
Macpherson was knighted in 1983. The same year he was appointed to the Queen's Bench in the High Court and was made Honorary Colonel of the 21st Special Air Squadron Regiment. In 1991, Macpherson was appointed honorary fellow at Trinity College, Oxford. In his legal career, Macpherson was involved in numerous important cases, including the conviction of the serial killer Robert Black in 1994. He retired in 1996. In 1997, Macpherson was appointed head of the inquiry into the murder of Stephen Lawrence. The inquiry was published in February 1999, and became known as The Macpherson Report. The report, in which Macpherson made over 70 recommendations, has been called "one of the most important moments in the modern history of criminal justice in Britain".