Dad is a nickname which may refer to:
- Dad Clark (1873-1956), American Major League Baseball player
- Dad Clarke (1865-1911), American Major League Baseball pitcher
- Dad Clarkson (1866-1911), American Major League Baseball pitcher
- Dad Hale (1880–1946), American Major League Baseball pitcher
- Dad Lytle (1862-1950), American Major League Baseball player
- William H. "Dad" Martin, photographer and successful postcard manufacturer in the early 1900s
- Dad Meek (1867-1922), American Major League Baseball catcher
- Harry Vail (died 1928), American collegiate rowing coach
- Dad Wheatley (1882–1961), Australian middle-distance runner