Luas (Irish pronunciation: [ˈl̪ˠuəsˠ]; Irish for "speed") is a tram/light rail system in Dublin, Ireland, which in 2015 carried 34.6 million passengers.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, both lines have been extended and split into different branches. The system now has fifty-four stations and 36.5 kilometres (22.7 mi) of track.

Luas is operated by Transdev, under tender from the Railway Procurement Agency (RPA). is a major part of the National Transport Authority's strategy (2000–2016). Three extensions to the existing Luas lines have been completed. Construction of a 6 km extension to the Green line to the North city centre and Broombridge, which will link both Green and Red lines, began in June 2013.

2015: 7 new Alston Citadis trams have been ordered for delivery by 2017 for the extension on the green line. They will be 54.6 metres in length (9 module) to carry 60 more people a total of 369 passengers per tram.