Patrick Arthur Devlin, Baron Devlin, PC (25 November 1905 - 9 August 1992) was a British lawyer, judge, and jurist. He wrote two important reports that influenced British government policy: the Wolfenden Report in 1957 and a report on Britain's involvement in Nyasaland in 1959. In 1985 he became the first British judge to write a book about a case he had presided over - the 1957 trial of suspected serial killer John Bodkin Adams.

Patrick Devlin was born in Chislehurst, Kent. His father was a Roman Catholic architect, originally from County Tyrone, and his mother was a Protestant, originally from Aberdeen. In 1909, a few years after Devlin's birth, the family moved to his mother's birthplace. The children were raised as Catholics, two of Devlin's sisters became nuns, and a brother became a Jesuit priest (another brother was an actor). Patrick Devlin joined the Dominican order as a novice after leaving Stonyhurst College, but left after a year for Christ's College, Cambridge.

At Cambridge, Devlin read both history and law, and he graduated in 1927, joining Gray's Inn and passing the bar exam in 1929. He worked as junior barrister for William Jowitt while Jowitt was Attorney-General, and by the late 1930s he had become a successful commercial lawyer. During the Second World War he worked for various ministries of the UK Government, and in 1948 Jowitt (by then Lord Chancellor) made Devlin a High Court judge. He was 42, the second-youngest such appointment in the 20th century. Devlin was knighted later that year.