Zak O'Sullivan (born 6 February 2005) is a British racing driver of Irish descent who is currently competing in the 2023 FIA Formula 3 Championship for Prema Racing. He most recently competed in the 2022 FIA Formula 3 Championship for Carlin. He is the champion of the 2021 GB3 Championship, and a member of the Williams Driver Academy.
He was awarded the Aston Martin Autosport BRDC Award for 2021.