Stansted Express is a sub-brand of Greater Anglia. It is the direct train service linking central London (Liverpool Street station) to Stansted Airport, one of London's major air hubs. Prior to February 2012, Stansted Express was operated by National Express East Anglia. Until 2004 Stansted Express was part of the WAGN franchise.

The service runs every 15 minutes with a journey time of between 46 minutes to over 1 hour during peak times.

Unlike the Heathrow Express and the Gatwick Express, the service also calls at stations between the airport and the central London Terminus. These are Tottenham Hale (which provides interchange with the London Underground and easier access to the West End and North London), Bishop's Stortford, Harlow Town and Stansted Mountfitchet (peak times and some weekend services only).

In the late 1980s, British Rail (BR) was extending the electrification north from London Liverpool Street towards Cambridge. Included in this plan was the construction of new branch line, diverging from the mainline at Stansted Mountfitchet, to serve the newly built Stansted Airport, which opened in 1991. Therefore, BR decided to build a dedicated fleet of units to work the new Stansted Express service.