President Xiomara Castro confirmed the murder and promised that the perpetrator and those involved would be held accountable for the fatal shooting.
Honduras in Central America is one of the world's most dangerous countries for environmental activists.
Lopez was active in trying to stop mining in a forest classified as a nature reserve. The iron ore mine near Tocoa in northern Honduras is planned to become an open-pit mine.
Lopez worked in Tocoa's city administration and was also politically active in the ruling party Libre. Recently, Lopez also accused party colleagues from Libre of having discussed receiving bribes with representatives of drug cartels in 2013. One of those pointed out was the president's brother-in-law, who left his seat in Congress after the revelation.
Lopez has previously highlighted the risks of questioning and criticizing social problems in Honduras.
You can never know what happens when you leave your home, and if you will return home, he said in an interview with AFP in 2021.
The independent organization Global Witness estimates that 18 environmental activists were killed in 2023, and that 148 activists were killed in the period 2012-2023.
