Each Party to the Convention is represented at sessions of the Convention bodies by a national delegation consisting of one or more officials empowered to represent and negotiate on behalf of their government.

Based on the tradition of the United Nations, Parties are organized into five regional groups, mainly for the purposes of electing the Bureaux, namely: African States, Asian States, Eastern European States, Latin American and the Caribbean States, and the Western European and Other States (the "Other States" include Australia, Canada, Iceland, New Zealand, Norway, Switzerland and the United States of America, but not Japan, which is in the Asian Group).

The five regional groups, however, are not usually used to present the substantive interests of Parties and several other groupings are more important for climate negotiations. Developing countries generally work through the Group of 77 to establish common negotiating positions. The G-77 was founded in 1964 in the context of the UN Conference on Trade and Development (UNCTAD) and now functions throughout the UN system. It has over 130 members. The country holding the Chair of the G-77 in New York (which rotates every year) often speaks for the G-77 and China as a whole. However, because the G-77 and China is a diverse group with differing interests on climate change issues, individual developing countries also intervene in debates, as do groups within the G-77, such as the African UN regional Group, the Alliance of Small Island States and the group of Least Developed Countries.

The Alliance of Small Island States (AOSIS) is a coalition of some 43 low-lying and small island countries, most of which are members of the G-77, that are particularly vulnerable to sea-level rise. AOSIS countries are united by the threat that climate change poses to their survival and frequently adopt a common stance in negotiations. They were the first to propose a draft text during the Kyoto Protocol negotiations calling for cuts in carbon dioxide emissions of 20% from 1990 levels by 2005.

The 50 countries defined as Least Developed Countries by the UN regularly work together in the wider UN system. They have become increasingly active in the climate change process, often working together to defend their particular interests, for example with regard to vulnerability and adaptation to climate change.

The 27 members of the European Union meet in private to agree on common negotiating positions. The country that holds the EU Presidency - a position that rotates every six months - then speaks for the European Union and its 27 member states. As a regional economic integration organization, the European Union itself can be, and is, a Party to the Convention. However, it does not have a separate vote from its members.

The Umbrella Group is a loose coalition of non-EU developed countries which formed following the adoption of the Kyoto Protocol. Although there is no formal list, the Group is usually made up of Australia, Canada, Japan, New Zealand, Norway, the Russian Federation, Ukraine and the US.

The Environmental Integrity Group (EIG), formed in 2000, comprises Mexico, Liechtenstein, Monaco, the Republic of Korea and Switzerland.

Several other groups also work together in the climate change process, including countries from the Organization of Petroleum Exporting Countries (OPEC), a group of countries of Central Asia, Caucasus, Albania and Moldova (CACAM), and countries that are members of organizations such as the League of Arab States and the Agence intergouvernementale de la francophonie.