The Galaxy Evolution Explorer (GALEX) is a NASA Explorer Mission launched on April 28, 2003, to perform the first space ultraviolet (UV) sky survey. GALEX includes imaging and grism surveys in two bands (1350-1750 Å and 1750-2750 Å), covering an all-sky imaging survey, a medium imaging survey, a deep imaging survey, and a nearby galaxy survey. The mission aims to study star formation in galaxies and its evolution over time, using UV properties to calibrate the relationship between UV and global star formation rates. GALEX will map the history of star formation in the universe over the redshift range 0 < z < 2 and probe the physical drivers of star formation in galaxies. The mission also supports a Guest Investigator program for a wide range of investigations. Early results from GALEX have provided insights into star formation in diverse contexts, the cosmic star formation history, and dust extinction. The mission's data legacy is expected to have broad and lasting impacts on astrophysics.The Galaxy Evolution Explorer (GALEX) is a NASA Explorer Mission launched on April 28, 2003, to perform the first space ultraviolet (UV) sky survey. GALEX includes imaging and grism surveys in two bands (1350-1750 Å and 1750-2750 Å), covering an all-sky imaging survey, a medium imaging survey, a deep imaging survey, and a nearby galaxy survey. The mission aims to study star formation in galaxies and its evolution over time, using UV properties to calibrate the relationship between UV and global star formation rates. GALEX will map the history of star formation in the universe over the redshift range 0 < z < 2 and probe the physical drivers of star formation in galaxies. The mission also supports a Guest Investigator program for a wide range of investigations. Early results from GALEX have provided insights into star formation in diverse contexts, the cosmic star formation history, and dust extinction. The mission's data legacy is expected to have broad and lasting impacts on astrophysics.