McCahill is a surname of Irish origin. The name refers to:
Persons Crystal McCahill (born 1983), Playboy Playmate of the month May 2009 Jim McCahill (born 1939), English football chairman Mark P. McCahill (born 1956), American developer of internet technology Romy McCahill (born 1993), Scottish model and beauty pageant titleholder Tom McCahill (1907–1975), American automotive journalist
See also Cahill (disambiguation)