Dublin Bus (Irish: Bus Átha Cliath) is an Irish state-owned bus operator providing services in Dublin. By far the largest bus operator in the city, it carried 145 million passengers in 2023. It is a subsidiary of Córas Iompair Éireann.
Dublin Bus was established on 2 February 1987, when Córas Iompair Éireann was split into 3 subsidiaries, Dublin Bus, Bus Éireann and Irish Rail. Dublin's main bus operator was formerly the Dublin United Transport Company. This company was incorporated into CIÉ in 1945.
In September 2011, Dublin Bus received a significant technological upgrade with its introduction of real time passenger information.