The East–West Line (EWL) is a high-capacity Mass Rapid Transit (MRT) line operated by SMRT in Singapore, running from Pasir Ris station in the east to Tuas Link station in the west, with an additional branch between Changi Airport and Tanah Merah stations. It is the second Mass Rapid Transit line to be built in Singapore. Coloured green on the rail map, the line serves 35 stations, 8 of which are underground. At 57.2 kilometres (35.5 mi), the line is the longest on the MRT network.

The Mass Rapid Transit system, locally known by the initialism MRT, is a rapid transit system in Singapore and the island country's principal mode of railway transportation. The system commenced operations in November 1987 after two decades of planning with an initial 6 km (3.7 mi) stretch consisting of five stations. The network has since grown to span the length and breadth of the country's main island – with the exception of the forested core and the rural northwestern region – in accordance with Singapore's aim of developing a comprehensive rail network as the backbone of the country's public transportation system, averaging a daily ridership of 3.4 million in 2019.