Mary S. Fosi is an environmental consultant and Chairperson of the Myrianthus Fosi Foundation for Biodiversity and Environmental Protection (MyFF), a nonprofit organisation that raises public awareness of environmental issues among local communities and promotes sustainable livelihoods. She began her professional career in the Cameroon public service in 1974, serving in several government ministries and institutions, including the Ministry of Social and Women’s Affairs, the Administrative Bench of the Supreme Court, the Ministry of Environment and Forestry, and the Ministry of Environment and Nature Protection. She held positions of increasing responsibility, including Chief of Service, Director, and Technical Adviser. She coordinated projects funded by the World Bank, the Global Environment Facility, and UNEP, and led government delegations to various international negotiations on environmental and forestry issues. She represented Cameroon in the African Ministerial Conference on the Environment (AMCEN), the Compliance Committee of the Cartagena Protocol on Biosafety, the Bureau of the Conference of the Parties to the Convention on Biological Diversity, the Conference of Central African Forest Ministers (COMIFAC), and the Bureau of the African Association for Public Administration and Management (AAPAM). After retiring from the Cameroon public service in 2009, she chaired various public tender boards and commissions in Cameroon until 2017. Since then, she has served as a consultant to FAO, UNEP, UNIDO, UNESCO, and GTZ.