Thomas Paul O'Sullivan (born 18 January 1995) is a Welsh professional footballer who plays as a midfielder for National League North club Gloucester City. A Wales youth international, he began his professional career with Cardiff City in 2012, making his debut in the League Cup in August 2012. He made his English Football League debut on loan at Port Vale in February 2015. After two loan spells at Newport County during the 2015–16 season, he signed for Colchester United in January 2017. He joined Torquay United on loan for the remainder of the 2017–18 season in January 2018. Having been released by Colchester, he signed with Hereford in October 2018. He spent just under two years with Hereford before making the move to Gloucester City in August 2020.