Thomas Niall O'Toole (born 23 September 1998) is an Irish professional rugby union player who plays as a prop for United Rugby Championship club Ulster and the Ireland national team.

Born in Drogheda, O'Toole lived in Ratoath, County Meath until he was six years of age before moving to Brisbane, Australia for ten years due to his father's work commitments,[3] where he attended Padua College.

[8][9] He made five senior appearances, including two starts, in the 2017–18 season,[10] and won Academy Player of the Year at the 2018 Ulster Rugby Awards.

[1] In the 2019–20 season he made 22 appearances, including ten starts,[1] and was named Young Player of the Year in the Ulster Rugby Awards.

[20] He was called up to the Ireland squad for their two-match tour of South Africa in July 2024.