Mottley's BLP won all 30 seats available, unseating opposition leader Ralph Thorne, after the prime minister built one of the strongest global profiles of any Caribbean leader, and was supported by voters across the country.
"Our mission first and foremost is to stop poor people from being poor and to remove injustice wherever it exists to create opportunities for people," Mottley said in a victory speech on election night.
Surrounded by supporters dressed in red, she announced that Friday would be a public bank holiday in Barbados.
The 60-year-old prime minister also promised to take care of Barbados' democracy, which last year celebrated 75 years since people earned the right to vote without owning property.
Her party has vowed to continue to focus on the economy, cost-of-living and the Caribbean nation's place on the international stage.
"The result is disappointing," Thorne said from the headquarters of the opposition Democratic Labour Party, although he expressed gratitude for a clean campaign.
The opposition has criticised issues of security and infrastructure, with Thorne saying policy should be focused on Barbadians' domestic priorities.
Barbados is the Caribbean's easternmost country, home to around 283,000 people and a little over half the size of Singapore.
(Reporting by Aida Pelaez-Fernandez; Editing by Kate Mayberry)
Prime Minister of Barbados Mia Mottley speaks during the General Debate of the 80th session of the United Nations General Assembly at United Nations headquarters in New York, New York, USA, 26 September 2025. EPA/SARAH YENESEL