Allin is both a surname and a given name. Notable people with the name include:
Surname:
Buddy Allin (1944–2007), American professional golfer
GG Allin (1956–1993), punk rock singer-songwriter and musician
Merle Allin (1953-present), American bassist
Norman Allin (1884–1973), British bass singer
Roger Allin (1848–1936), American politician
Sir Thomas Allin, 1st Baronet (17th century), English naval officer
Given name:
Allin Braund (1915–2004), British artist
Eric Allin Cornell (born 1961), American physicist