Environmental constitutionalism is a relatively recent phenomenon at the confluence of constitutional law, international law, human rights, and environmental law. It embodies the recognition that the environment is a proper subject for protection in constitutional texts and for vindication by constitutional courts worldwide. This entry provides an overview of the extent to which countries have adopted constitutional protections to protect the environment either for people or for its own sake, focusing on the origins, establishment, emergence and enforceability of environmental constitutionalism around the globe.