Dorgan (Ó Deargáin) is an Irish surname, derived from dearg "red" (compare Craoibh Dearg). Notable people with the surname include:
Byron Dorgan (born 1942), United States senator from North DakotaHoward Dorgan (1932–2012), American academic known for his research and writing on religion in AppalachiaJerry Dorgan (1856–1891), American baseball playerJim Dorgan (born 1930), Australian rules football playerJohn L. Dorgan (born 1879), known as Ike Dorgan, American boxing manager, and publicity manager for the Madison Square Garden, founding partner of The Ring magazineJoseph "Joe" Dorgan (born 1975), American professional wrestler and personal trainer, best known as Johnny SwingerMike Dorgan (1853–1909), American baseball playerPatrick Dorgan, Danish singerRichard W. Dorgan (1892–1953), American cartoonistSeán Dorgan (born 1968), Irish politicianTad Dorgan (1877–1929), American cartoonistTheo Dorgan (born 1953), Irish poet, writer and lecturer