Frank Gavan Duffy, Irish-Australian lawyer and judge, 4th Chief Justice of Australia (d. 1936)

Sir Frank Gavan Duffy, KCMG, KC (29 February 1852 – 29 July 1936) was an Australian judge who served as the fourth Chief Justice of Australia, in office from 1931 to 1935. His total service on the High Court of Australia was from 1913 to 1935. Prior to his judicial career, he was one of Victoria's most prominent barristers.