The bank has broken different retailer types into five categories: including groceries, restaurants, petrol, premium rate websites and phone lines – and gambling.
Barclays was advised by several groups, including the Money Advice Trust, and the measure means any payments falling within a "turned off" category will be automatically declined.
Barclays Managing Director Catherine McGrath said: "We are always looking for new ways to support our customers and make it easier for them to manage their finances."
GambleAware CEO Marc Etches said: "GambleAware welcomes this initiative by Barclays, which we hope will encourage other banks to do the same.
"There are 340,000 problem gamblers in Britain and a further 1.7 million at risk and initiatives like this can play an important role in helping to reduce gambling-related harms."
In October, Letou CEO Paul Fox suggested a similar policy during an exclusive interview with Gambling Insider.
