Environmental defenders or environmental human rights defenders are individuals or collectives who protect the environment from harms resulting from resource extraction, hazardous waste disposal, infrastructure projects, land appropriation, or other dangers. In 2019, the UN Human Rights Council unanimously recognised their importance to environmental protection. The term environmental defender is broadly applied to a diverse range of environmental groups and leaders from different cultures that all employ different tactics and hold different agendas. Use of the term is contested, as it homogenizes such a wide range of groups and campaigns, many of whom do not self-identify with the term and may not have explicit aims to protect the environment.

Environmental conflicts, socio-environmental conflict or ecological distribution conflicts (EDCs) are social conflicts caused by environmental degradation or by unequal distribution of environmental resources. The Environmental Justice Atlas documented 3,100 environmental conflicts worldwide as of April 2020 and emphasised that many more conflicts remained undocumented.