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Globally, groundwater represents a critical natural resource that is affected by changes in natural supply and renewal, as well as by increasing human demand and consumption. However, despite its critical role, groundwater is difficult to accurately quantify as it is beneath the Earth surface. Here, we review several state‐of‐the‐art remote sensing techniques useful for local‐ to global‐scale groundwater monitoring and assessment, including proxies for groundwater extraction. These include inferring changes in subsurface water from mass changes using gravitational measurements, and analyzing changes in the Earth surface height using Interferometric Synthetic Aperture Radar, Light Detection and Ranging, Airborne Electromagnetic Systems, and satellite altimetry. Remote sensing information is often used in tandem with ground‐based observations such as hydraulic head in wells, Global Navigational Satellite System monitoring, and numerical modeling to complement the space‐based approaches. In the future, fusing different remote sensing techniques capable of operating in various environments will yield additional insight on the state and rate of use for groundwater across the globe. Key Points: Accurately measuring and monitoring groundwater storage and fluxes is critical for water, food, and energy securityRemote sensing approaches such as gravitational measurements, Interferometric Synthetic Aperture Radar, Global Navigational Satellite System, lidar altimetry, and Airborne Electromagnetic Systems can yield indirect yet valuable information about groundwaterFusing multiple remotely sensed data sets or employing other tools such as numerical models increase the applicability of individual approaches [ABSTRACT FROM AUTHOR]