The United Nations Environment Programme (UNEP) was established by the UN General Assembly in 1972. Its mission is "to provide leadership and encourage partnership in caring for the environment by inspiring, informing and enabling nations and peoples to improve their quality of life without compromising that of the future generations."

Since its establishment, environmental law has been one of the priority areas of UNEP, in line with the mandate accorded by the UN General Assembly Resolution 2997 (XXVII) and subsequent decisions of the Governing Council of UNEP. UNEP’s Environmental Law activities are carried out within the framework of strategic Programmes for the Development and Periodic Review of environmental Law (The Montevideo Programmes) approved by the Governing Council every ten years.

UNEP aims at promoting the coherent implementation of the environmental dimension of sustainable development within the United Nations system. Agenda 21 designated UNEP as the principal United Nations body in the field of the environment. Among the priority areas identified in Agenda 21 on which UNEP should concentrate, are the following:

• Further development of international environmental law, in particular conventions and guidelines, promotion of its implementation and coordinating functions arising from an increasing number of international legal agreements, inter alia, the functioning of the secretariats of the Conventions;(Agenda 21, Chapter 38 - chap. 38.22 (h)
• Provision of technical, legal and institutional advice to Governments, upon request, in establishing and enhancing their national legal and institutional frameworks, in particular, in cooperation with UNDP capacity-building efforts;
  (Agenda 21, Chapter 38 - chap 38.22 (l)

UNEP’s role in the development of environmental law has been further strengthened in the follow-up to the United Nations Conference on Environment and Development (UNCED – Rio Conference, also known as the Earth Summit). UNEP’s role as leading global environmental authority has also been reiterated in the 1997 Nairobi Declaration on the Role and Mandate of UNEP and subsequent documents. In addition, the Malmö Ministerial Declaration emphasized the fact that international environmental law frameworks and the development of national law provide a sound basis for addressing the major environmental threats of the twenty-first century.