The GEF provides funding to assist developing countries in meeting the objectives of international environmental conventions. The GEF serves as a "financial mechanism" to five conventions: Convention on Biological Diversity (CBD), United Nations Framework Convention on Climate Change (UNFCCC), Stockholm Convention on Persistent Organic Pollutants (POPs), UN Convention to Combat Desertification (UNCCD), and Minamata Convention on Mercury. 

The conventions, for which the GEF serves as financial mechanism, provide broad strategic guidance to the two governing bodies of the GEF: the GEF Council and the GEF Assembly. The GEF Council converts this broad guidance into operational criteria (guidelines) for GEF projects. 

The GEF is the designated institutional structure operating the financial mechanism of the CBD; it applies the guidance, including policy, strategy, program priorities, and eligibility criteria relating to access to and use of its resources from the Conference of the Parties.

At every ordinary meeting of the Conference of the Parties (COP), the GEF provides a report on its biological diversity activities. The Executive Secretary regularly provides updates on the development of biodiversity issues, under the Convention to the GEF Council. The CBD relationship with the GEF is governed by a Memorandum of Understanding between the COP to the Convention on Biological Diversity and the GEF Council (COP 3 Decision III/8).

The contribution of countries to climate change and their capacity to prevent and cope with its consequences vary enormously. Under the UNFCCC and the Kyoto Protocol, developed country Parties (Annex II Parties) provide financial resources to assist developing country Parties for implementing the Convention. To facilitate this, the Convention designated the GEF as the financial mechanism, subject to review every four years. The GEF will also serve the Paris Agreement reached by 195 nations at the COP21 in Paris.

The financial mechanism is accountable to the Conference of the Parties, which decides on its climate change policies, program priorities, and eligibility criteria for funding, based on advice from the Subsidiary Body For Implementation.

In addition to providing guidance to the GEF, Parties have established three special funds: the Special Climate Change Fund (SCCF) and Least Developed Countries Fund (LDCF), under the Convention and managed by the GEF; and the Adaptation Fund (AF), under the Kyoto Protocol for which the GEF provides secretariat services.

The relationship between the COP to the UNFCCC and the GEF Council was agreed to in a memorandum of understanding (MOU) contained in decisions 12/CP.2 and 12/CP.3

Article 14 of the Stockholm Convention entrusts the GEF as its financial mechanism, following the principles laid down under Article 13 relative to the new and additional financial resources necessary to enable developing countries and countries with economies in transition to implement the Convention. A Memorandum of Understanding between the Conference of the Parties and the Council of the GEF gives effect to this relationship. Guidance to the financial mechanism has been provided by each subsequent COP meeting.

At every ordinary meeting of the Conference of the Parties, the GEF provides a report on its activities related to persistent organic pollutants.

The Stockholm Convention’s objectives include:

  • Eliminating the production and use of specific POPs;
  • Restricting the production and use of DDT only to disease vector control under WHO guidelines;
  • Restricting exports of POPs;
  • Developing strategies for identifying stockpiles of POPs and products containing POPs;
  • Taking measures to ensure that POPs wastes are managed and disposed of in an environmentally sound manner;
  • Developing strategies for identifying sites contaminated by POPs;
  • Ensuring that PCBs are managed in an environmentally sound manner and, by 2025, take action to remove PCBs from use;
  • Developing and implementing action plans to identify the sources and reduce releases of POPs byproducts; and
  • Identifying other chemicals with POPs characteristics and bringing them under the control of the Convention. 

On September 2003, the Conference of the Parties accepted the GEF as a financial mechanism of the UNCCD. The funds allocated by the GEF, support activities that address the issue of desertification and deforestation.

The GEF is the main financial mechanism of the Minamata Convention on Mercury, together with the Specific International Programme (SIP). The financial mechanism was established under Article 13 of the Convention text, and the First Conference of the Parties (COP-1) defined its guidance in 2017, on strategies, policies, and eligibility for access to its resources. The relationship between the GEF and the COP is defined by a Memorandum of Understanding.

The GEF has been charged with raising and disbursing grants for projects and programs to reduce and eliminate mercury pollution. GEF grants are supporting a wide range of activities under the Minamata Convention. These activities include inventories, implementation plans, and investments in technology for reduction and elimination of mercury, such as:

The GEF, although not linked formally to the MP, supports implementation of the Protocol in Countries with Economies in Transition. The GEF Secretariat has exchanged letters with the secretariats of the Montreal Protocol and the Multilateral Fund that show areas of cooperation and coordination.

The GEF Secretariat regularly participates to meeting of the Parties to the MP and other subsidiary bodies, and informs the parties of its work of relevance. The Executive Secretary of the Ozone Secretariat provides regular updates on the development under the Protocol to the GEF Council and Assembly.

The GEF is also associated with many global and regional multilateral agreements that deal with international waters or transboundary water systems. As such, the GEF assist its recipient countries with international waters issues as they undertake work under the following conventions:

  • The Global Ship Ballast Water Treaty
  • The UN Law of the Sea Treaty
  • The MARPOL treaty for shipping (International Convention for the Prevention of Pollution From Ships)
  • The UN Agreement on conservation and management of straddling fish stocks and highly migratory fish stocks. 

The GEF also supports various UN Agency Action Programs like the Barbados Programme of Action, the Global Programme of Action (GPA), Code of Conduct for Fisheries. However, more often the GEF supports and help negotiate regional conventions like the Barcelona, Cartagena, Bucharest, and Danube Conventions. 

For successful implementation of international conventions for which GEF is serving as the financial mechanism, developing countries need capable individuals and effective institutions and organizations to work together in a well-functioning political, economic ,and social system – also called as "the enabling environment."

Capacity development is a primarily endogenous and domestically driven process that depends on clearly answering questions involving the appropriate capacity for what and for whom. Capacity development in the GEF is designed to adhere fully to the concerns and priorities expressed by the international community (for example, the 2005 Paris Declaration on Aid Effectiveness), an inherently political and complex process that cannot be rushed, with outcomes that cannot be expected to evolve in a controlled and linear fashion.