The event will be renamed the Barclays ATP World Tour Finals and will replace the Tennis Masters Cup, which is currently held in Shanghai's Qi Zhong Tennis Center.
Shanghai has played host since 2005.
Next year, the season-ending event will be held in London's O2 Arena, featuring the world's top eight singles players and eight doubles teams.
Elizabeth Chambers, chief marketing officer of global retail and commercial banking at Barclays, said: "We are very pleased to be bringing the ATP Barclays World Tour Finals to London next year.
"It provides a solid platform for Barclays to deepen our relationships with key clients in line with our growth strategy, while also heightening our global profile."
Barclay's five-year deal is worth around £3.5m a year and includes the option to extend to eight years.