First proposed to exist by Dmitri Mendeleyev in 1871 based on gaps in his newly created Periodic Table of Elements, gallium was discovered spectroscopically by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875. Later that same year, Lecoq was able to obtain pure gallium through the electrolysis of a solution of gallium hydroxide (Ga(OH)₃) in potassium hydroxide (KOH). Trace amounts of gallium are found in diaspore, sphalerite, germanite and bauxite as well as in the byproducts of burning coal.

Gallium melts near room temperature and has one of the largest liquid ranges of any metal, so it has found use in high temperature thermometers. Gallium easily forms alloys with most metals and has been used to create low melting alloys. Gallium is used as a doping material for semiconductors and has been used to produce solid-state items like transistors and light emitting diodes. Gallium arsenide (GaAs) can produce laser light directly from electricity. Large amounts of gallium trichloride (GaCl₃) have been gathered to build the Gallium Neutrino Observatory, an observatory located in Italy built to study particles called neutrinos which are produced inside the sun during the process of nuclear fusion.