Berta Caceres, a 43-year-old teacher, was shot and killed by two men at her home in La Esperanza, Honduras, 112 miles (180 kilometers) west of the capital, Tegucigalpa, Honduran security minister Julian Pacheco said, condemning the attack.
One other person was wounded in the incident, which is under investigation.
The murder rate in Honduras is one of the highest in the world.
Caceres, who had received death threats, won the Goldman Environmental Prize in 2015 for her struggle to prevent the construction of a $50 million dam that threatened to displace hundreds of Indians.
“She was a fearless environmental hero. She understood the risks that came with her work, but continued to lead her community with amazing strength and conviction,” John Goldman, president of the Goldman Environmental Foundation, said of Caceres.
Erika Guevara-Rosas, Americas director at Amnesty International, said “The cowardly killing of Berta is a tragedy that was waiting to happen. For years, she had been the victim of a sustained campaign of harassment and threats to stop her from defending the rights of indigenous communities.”
The project, which was subcontracted by a local company to Chinese builder Sinohydro, has been temporarily suspended thanks to protests led by Caceres.
(FRANCE 24 with REUTERS)