In this paper, we provide an overview of the scientific potential of the THEIA mission concept. THEIA consists of a 4‐meter telescope diffraction limited to 300 nm, and a 40‐meter external occulter to provide high‐contrast imaging. Operating from 250 to 1000 nm, it will provide a rich family of science projects, including exoplanet characterization, ultraviolet spectroscopy, and very wide‐field imaging. We discuss a number of the key science areas and how the capabilities of THEIA can provide novel and interesting results in these areas.