The Green Line is one of the two lines of Dublin's Luas light rail system. The Green Line was formerly entirely in the south side of Dublin city. It mostly follows the route of the old Harcourt Street railway line, which was reserved for possible re-use when it closed in 1958. The Green Line allows for passengers to transfer at O’ Connell GPO and Marlborough to Luas Red Line services and also allows commuters to use Broombridge as an interchange station to reach outer suburbs such as Castleknock and Ongar as well as Iarnrod Éireann services.

Luas is a tram system in Dublin, Ireland. There are two main lines: the Green Line, which began operating on 30 June 2004, and the Red Line which opened on 26 September 2004. Since then, the red line has been extended and split into different branches further out of the city and the green line has been extended north and south as a single line. Since the northern extension of the green line in 2017, the two lines intersect in the city centre. The system now has 67 stops and 42.5 kilometres (26.4 mi) of revenue track, which in 2023 carried 48.2 million passengers, an increase of 24% compared to 2022.