ECOLEX is a joint initiative of IUCN, UNEP and FAO to build capacity by providing the most comprehensive global source of environmental law worldwide. It is a collection and directory of environmental legislation (national and multinational).

ECOLEX allows users to undertake a common online search of all of the databases of IUCN (ELIS - the Environmental Law Information System), FAO (FAOLEX) and UNEP (CELIB - Computerised Environmental Law Information Base). Through a single search, users can access bibliographic and analytical information on multilateral legal instruments and treaties, national legislation, "soft law" and related documents, judicial decisions, law and policy literature and more for selected subject areas and key words.

Users can search using subject area, keyword, country, or date. Databases are available in English, French and Spanish.