Carstairs is a surname. Notable people with the surname include:
Betty Carstairs (1900–1993), British power boat racer
Carroll Carstairs (1886–1948), American art dealer
John Paddy Carstairs (1910–1970), British film and television director
Sharon Carstairs (born 1942), Canadian politician
Fictional characters:
Lt. Fairfax and Lt. Carstairs, characters from the BBC sitcom 'Allo 'Allo!
James "Jem" Carstairs character from the Infernal Devices series by Cassandra Clare.