Hamfatter are a pop rock band from Cambridge, UK, formed in 2002. The band are known primarily for their appearance on BBC's Dragons' Den. The core of the band is a three-piece, comprising Eoin O'Mahony (vocals, bass guitar, piano), James Ingham (guitar, backing vocals) and Mark Ellis (drums).

Eoin O'Mahony is the younger brother of the author Daniel O'Mahony.