John Joseph O'Neill (born 26 August 1957) is a musician who is the rhythm guitarist and principal songwriter of the punk rock/new wave band the Undertones.

[2] John O'Neill wrote the majority of the band's singles and a number of album tracks[3] (occasionally collaborating with his brother Damian or Michael Bradley).

Since then, the band (who have a new lead singer, fellow Derry native Paul McLoone who also serves as a radio presenter for the Irish national and independent radio station Today FM) have released two more albums and performed a number of gigs in both the UK, Ireland, Europe and North America.

[5] In 1985, the O'Neill brothers formed That Petrol Emotion, an acclaimed rock act that disbanded in 1994.

Despite some positive reviews in the music press, they only had one notable chart appearance and disbanded shortly after the release of their only album in 1998.