Cosby is a surname. Notable people with the surname include:
Alexander Cosby (1685–1742), Irish military officerAndrew Cosby (born 1968), American comic book creator, film producer, and screenwriterBill Cosby (born 1937), American comedy actorCamille Cosby (born 1944), American author and wife of Bill CosbyDabney Cosby (1793–1862), American architect and builderDudley Cosby, 1st Baron Sydney (1730–1774), Irish politician and diplomatEnnis Cosby (1969–1997), American student and son of Bill Cosby who was murdered in 1997Erika Cosby (born 1965), artist and daughter of Bill CosbyFrancis Cosby (1510–1580), English soldier and settler in IrelandGeorge B. Cosby (1830–1909), Confederate States Army officerGerry Cosby (1909–1996), American ice hockey player and businessmanHenry Cosby (1928–2002), American songwriter and record producerJessica Cosby (born 1982), American hammer throwerJoseph Hathaway Cosby (1902–1998), American pastor, US Army chaplain, and the second President of Hargrave Military AcademyPhillips Cosby (1729–1808), Royal Navy officerQuan Cosby (born 1982), American football playerRita Cosby (born 1964), TV reporterWilliam Cosby (1690–1736), British nobleman and governor of the New York Colony