ICLEI's members are committed local and regional governments, representing diverse communities across the globe. They guide our efforts to make sustainability fundamental to all development and to scale up sustainable urban development worldwide. ICLEI members guide our work, shape our strategy, and support the mission, mandate, and principles established in our statutes. They are eligible to vote and participate in the governance bodies of the entire network.

Membership is open to all local and regional governments, as well as their global, regional, national and sub-national associations. They contribute an annual membership fee which varies regionally and according to population and per capita gross national income.