Ground, airborne and marine gravity data are essential for increasing the resolution and accuracy of satellite gravity data as they capture small-scale gravity features not visible (or attenuated) to the satellite gravity missions. Well-distributed terrestrial gravity data is essential for the determination of the geoid and, consequently, for the establishment and maintenance of physical height reference systems. Time and space-dependent changes of gravity yield information on the distribution and movement of Earth’s masses. Time series of gravity data are essential for modelling and monitoring geodynamic and geophysical processes. Satellite gravimetry provides a unique, global, and homogeneous data set of mass anomalies within or on the surface of the Earth. However, current satellite gravimetry is unable to resolve structures smaller than a few hundred kilometres. To increase the spatio-temporal resolution of satellite gravimetry and to be able to detect short-term and small-scale mass changes, terrestrial gravimetry is essential. Terrestrial gravimeters can detect changes in mass distribution within a radius of a few hundred meters from the instrument. Thus, terrestrial gravimetry is an important tool to monitor low-frequency seismicity, volcanic systems, geothermal reservoirs, effects of irrigation or water withdrawal, impacts of large building projects, etc. Terrestrial gravity data is also essential for geophysical prospection, and it is widely used in the exploration of natural resources like oil and gas, as well as in mining and in geotechnical, archaeological, metrological and geomatics studies. The following geodetic products are key to realising, monitoring and applying this Essential Geodetic Variable: