Guglielmo Righini (Castelfranco Veneto, 1908 – Florence, 1978) was an Italian astronomer specializing in solar physics. He joined the Arcetri Observatory in Florence in 1928 and became its director in 1953, succeeding Giorgio Abetti, while also serving as professor of astronomy at the University of Florence. Under his leadership Arcetri became a center for solar physics and solar radio astronomy and joined the European JOSO project to identify prime observing sites. A historian of science as well, he devoted much of his later work to Galileo. In 1961 he led one of the first observations of a solar eclipse from an airborne observatory above 5,000 metres. With journalist Giancarlo Masini he co-authored the popular Terra-Luna yearbook.