Guinness (Irish: Mag Aonghuis) is a surname. Notable people with the surname include:
Alec Guinness (1914–2000), British actor
Arthur Guinness (1725–1803), founder of Guinness beer
Arthur Guinness (New Zealand politician) (1846–1913)
Bunny Guinness (born 1955), British landscape architect and broadcaster
Daphne Guinness (born 1967), artist
Desmond Guinness (1931–2020), Irish writer on Georgian art and architecture
Humphrey Patrick Guinness (1902–1986), British polo player
Jasmine Guinness (born 1976), model and designer
Kenelm Lee Guinness (1887–1937), racing driver and spark plug manufacturer
Matthew Guinness (born 1940), British actor
Oonagh Guinness (1910–1995), Anglo-Irish socialite and society hostess
Os Guinness (born 1941), author
Peter Guinness (disambiguation), multiple people