TR1 may refer to: C++ Technical Report 1, a document proposing additions to the C++ Standard Library Regency TR-1, an early transistor radio model Triumph TR1 / 20TS, an unsuccessful automobile prototype Tomb Raider (1996 video game), the first video game in the Tomb Raider series TR-1A or TR-1B, variants of the Lockheed U-2 surveillance aircraft Hitachi TR.1 TR.1, see Orenda Engines TR1, a postal district in the TR postcode area TAS1R1, a taste receptor Tri-R KIS TR-1, an American aircraft design Lyulka TR-1, first Soviet turbojet engine Tropical Race 1, a strain of Fusarium oxysporum that causes the Panama disease Type 1 regulatory T cell (Tr-1), a T-lymphocyte lineage with immunoregulatory function Yamaha TR-1 High Output Boating Engine VR Class Tr1, a Finnish locomotive class