The firm said it would close all its stores “in a phased manner” between the end of August and the end of September.
This includes 19 stores that were already scheduled to close in July as their leases were expiring.
The company has not disclosed how many employees the closures will affect, but will shortly start a consultation process with the staff.
A Gap spokesperson said the decision followed a strategic review of its European business.
As a result, Gap is also looking to offload its stores in France and Italy.
The company said it was in negotiations with another firm to take over all of its French stores.
In Italy, Gap said it was in discussions with a partner for the potential acquisition of the stores there.
“We believe in Gap’s global brand power. We are executing against Gap’s Power Plan and partnering to amplify our global reach,” the spokesperson said.
“We are not exiting the UK market. We will continue to run and operate our Gap e-commerce business in the United Kingdom and Republic of Ireland.”