University of Giessen, official name Justus Liebig University Giessen, is a large public research university in Giessen, Hesse, Germany. It is one of the oldest institutions of higher education in the German-speaking world. It is named after its most famous faculty member, Justus von Liebig, the founder of modern agricultural chemistry and inventor of artificial fertiliser. It covers the areas of arts/humanities, business, dentistry, economics, law, medicine, science, social sciences and veterinary medicine. Its university hospital, which has two sites, Giessen and Marburg, is the only private university hospital in Germany.

Giessen, spelled Gießen in German, is a town in the German state (Bundesland) of Hesse, capital of both the district of Giessen and the administrative region of Giessen. The population is approximately 90,000, with roughly 37,000 university students.