Nisreen Elsaim is an environmental and climate activist. She holds a bachelor's degree in physics and a master's degree in renewable energy from the University of Khartoum, Sudan. 

Elsaim served as the general coordinator for Youth and Environment (YES) — Sudan and chaired and co-founded the Sudan Youth Organization on Climate Change (SYOCC). 

As part of many regional and international platforms, Elsaim has led and mentored a large number of young people within the Official Youth Constituency of the United Nations Framework Convention on Climate Change (YOUNGO), Pan African Climate Justice Alliance (PACJA), Abu Dhabi Youth Voices, and others. She is a junior negotiator with the African Group of Negotiators in Technology Transfer, focusing on the policies of countries regarding climate change and renewable energies and has written several policy papers on climate change, renewable energy, gender, and youth empowerment.

In 2020, Elsaim was chosen to chair the UN Secretary General’s Youth Advisory Group on Climate Change along with six other young climate activists. She is also one of the first cohorts of Marianne Initiative for Human Rights Defenders, an initiative by the French President. 

Recently, she was chosen to be part of the Young African Leaders Program at the European University Institute, an EU-sponsored program.