MRT may refer to:
The Metropolitan Rapid Transit or MRT is a rapid transit system serving the Bangkok Metropolitan Region in Thailand. The first section of the Blue Line between Hua Lamphong and Bang Sue opened in 2004 as Bangkok's second public transit system, while the MRT Purple Line opened in August 2016. The MRT is operated by the Bangkok Expressway and Metro Public Company Limited (BEM) under a concession granted by the Mass Rapid Transit Authority of Thailand (MRTA). Along with the Bangkok Mass Transit System (BTS, also called the Skytrain), and the Airport Rail Link (ARL), the MRT is part of Bangkok's rail transportation infrastructure.
The MRT serves more than 240,000 passengers each day. It has 35 operational stations along of underground route. The Blue Line, officially the Chaloem Ratchamongkhon Line, was the first of the two lines currently in operation. As of 2016, two extensions of the Blue Line are under construction. When completed, the Blue Line will become a loop line around the centre of Bangkok, with an extension to Bang Khae on its western side. The MRT Purple Line, also owned by MRTA, began its full service on August 6, 2016. MRT Purple Line will connect Bang Sue with Nonthaburi in the north-west, and will be the first public transit line outside the Bangkok Metropolitan Administration.
The MRT line is officially known in Thai as rotfaifa mahanakhon (รถไฟฟ้ามหานคร) or "metropolitan electric train", but it is more commonly called rotfai taidin (รถไฟใต้ดิน), literally, "underground train". The metro has a fleet of 19 trains; the 19th train entered service in October 2007 after a major accident.