The Technical Secretaries of the eight UN agencies IMO, FAO, UNESCO-IOC, WMO, IAEA, UN, UNEP, and UNIDO, along with the Administrative Secretary, nominated by IMO which currently serves as the Administrative Secretariat, form the Executive Board of GESAMP. The Executive Board meets together with the Chairperson and Vice-Chairperson of GESAMP as the Executive Committee which is responsible for the general oversight of GESAMP as well as planning and approving the GESAMP budget and work plan, selecting the GESAMP Members from the Pool of Experts, proposing provisional agendas for GESAMP sessions, and adopting terms of reference for its working groups.

GESAMP actively seeks to work with Partner Organizations through co-sponsorship of Working Groups and other activities. Governments and organizations may initiate partnerships, for example by proposing potential work for GESAMP. The preferred arrangement for partnership activities is to use the GESAMP structure and to produce products under the GESAMP banner, with partner organizations as full and equal co-sponsors. If a Working Group is co-sponsored by both GESAMP and external partner organizations, it is preferred that Working Group Members be selected from the GESAMP pool and the output published in GESAMP Reports and Studies. Nevertheless partner organizations act equally with the Executive Committee in the selection of Working Group members, development of terms of reference and work plan, etc., and receive full recognition as equal co-sponsors of the Working Group. The primary considerations for GESAMP in establishing partnerships are making GESAMP's activities inclusive and safeguarding the scientific credibility and independence of GESAMP's advice. Individual groups or supporting organizations may similarly support GESAMP's work while not actively participating in it through contributions to the GESAMP Trust Fund or by other means. Such supporters are prominently identified on the GESAMP web site and in promotional materials.