The Thomson–East Coast Line (TEL) is a high-capacity Mass Rapid Transit (MRT) line in Singapore. Coloured brown on the rail map, it is fully underground. When fully completed, the sixth line on the country's MRT network will serve 32 stations around 43 kilometres (27 mi) in length, becoming one of the world's longest driverless rapid transit lines. It runs along a combined north–south and east–west corridor, starting in the north at Woodlands town, passing through Upper Thomson and the towns of Ang Mo Kio and Bishan, heading south to the city-centre at Orchard Road and Marina Bay, subsequently heading eastwards along the eastern coast of the country through Kallang, Marine Parade and southern Bedok before ending at Upper East Coast.

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.