Great Western Railway (GWR) is a British train operating company owned by FirstGroup that operates the Greater Western passenger railway franchise. It manages 197 stations and its trains call at over 270. GWR operates long-distance inter-city services along the Great Western Main Line to and from the West of England and South Wales, inter-city services from London to the West Country via the Reading–Taunton line, and the Night Riviera sleeper service between London and Penzance. It provides outer-suburban services in West London; commuter services from its London terminus at London Paddington to the Thames Valley region, including parts of Berkshire and Buckinghamshire, and Oxfordshire; and regional services throughout the West of England and South Wales to the South coast of England. Great Western Railway provides and maintains the Electrostar Class 387 fleet for Heathrow Express.

FirstGroup plc is a British multi-national transport group, which is based in Aberdeen in the north-east of Scotland. The company operates transport services in the United Kingdom and the Republic of Ireland. It is listed on the London Stock Exchange and is a constituent of the FTSE 250 Index.