By Adria Calatayud

British American Tobacco plans to cut or outsource nearly a fifth of its workforce, as part of a strategy to reduce costs and streamline its operations.

The Lucky Strike and Kent cigarette maker said Monday that it plans to reduce about 5,500 jobs by the end of the year, on top of around 3,500 roles that it moved to outsourcing partners like Accenture. The company employs 47,000 people globally, according to its website.

BAT said its supply-network operations in the U.K. and Singapore, as well as certain roles across its global service hubs in Costa Rica, Mexico, Poland, Romania and Malaysia, moved to Accenture.

The company also consolidated its factory network over the past two years, which included the closure of its Heidelberg plant in South Africa, it said.

The changes are part of a restructuring program BAT launched last year, which aims to deliver about 600 million pounds ($792.1 million) in annual cost savings by 2028, the company said. The operational changes are progressing as planned, it added.

Write to Adria Calatayud at adria.calatayud@wsj.com