Gaff is a surname. Notable people with the surname include:
Andrew Gaff (born 1992), Australian rules footballer Brent Gaff (born 1958), American baseball player Jerry G. Gaff (born 20th century), American educational scholar John Gaff (1927–2013), British Army officer Sheila Gaff (born 1989), German martial artist
Other uses Thomas Gaff House (disambiguation)