| Guy Callaghan | |
| Fullname: | Guy James Callaghan |
| Strokes: | Butterfly |
| Birth Date: | 1970 9, df=yes |
| Birth Place: | Hastings, Hawke's Bay |
| Weight: | 72kg (159lb) |
Guy Callaghan (born 7 September 1970 in Hastings, Hawke's Bay) is a former butterfly swimmer from New Zealand, who competed at the 1992 Summer Olympics in Barcelona, Spain for his native country.
His biggest success came in 1995, at the second edition of the FINA World SC Championships in Rio de Janeiro, Brazil, where Callaghan won the gold medal with the Men's 4x100 Medley Relay Team. This was a New Zealand record time and was the 4th fastest time ever recorded.