William Mackey may refer to:
William Mackey (Fenian) (1841–1884), member of the Fenian Brotherhood and the Clan na Gael William Mackey (Jesuit) (1915–1995), Canadian Jesuit educationist and founder of the modern educational system of Bhutan William F. Mackey (1858–1912), American lawyer and politician from New York William Davis Mackey (1913–?), American lawyer and politician from Indiana Bill Mackey (1927–1951), American racecar driver
See also William Mackie (1799–1860), early Australian settler and judge William Mackie (geologist), Scottish geologist William C. Mackie, American college football player and coach