The International Union of Geodesy and Geophysics (IUGG) was established on 28 July 1919 in Brussels, Belgium at the Inaugural General Assembly of the International Research Council (now the International Science Council) to promote activities of already-existing international scientific societies dealing with geodesy, terrestrial magnetism and electricity, meteorology, physical oceanography, seismology, and volcanology.

Today IUGG is a non-governmental international scientific organization dedicated to advancing, promoting, and communicating knowledge of the Earth system, its space environment, and the dynamical processes causing change. Through its constituent Associations and more than 100 commissions, working groups and services, IUGG convenes international assemblies and workshops, undertakes research, collects observations, validates and endorses scientific products, defines standards and best practice, gains insight, coordinates activities, liaises with other scientific, national, international and intergovernmental bodies, offers advice to a variety of stakeholders, passes resolutions, issues policy documents, contributes to education and outreach, and works to expand capabilities and participation worldwide.