This article is about the city of Giessen; for other meanings see Giessen (disambiguation).

Giessen is a university town in the district of Giessen in Central Hesse and, with 90,131 inhabitants (31 December 2020), the seventh largest city in the state of Hesse and one of the state's seven special-status cities. As the seat of the administrative district of Gießen and the county, it is the administrative centre of Central Hesse, an important transport hub and one of the region's major centres.

Together with Wetzlar in the Lahn-Dill district, ten kilometres to the west, the city forms an agglomeration area with a population of around 200,000, and the surrounding region has a population of around 275,000. Further away are the cities of Marburg (Marburg-Biedenkopf district) up the River Lahn, Fulda (Fulda district) on the other side of the Vogelsberg, Siegen (Siegen-Wittgenstein district) in South Westphalia, Friedberg (Hesse) and Bad Nauheim in the Wetterau district, and Limburg an der Lahn (Limburg-Weilburg district) on the edge of the Westerwald.

The city is home to the Justus Liebig University, several departments of the Technical University of Central Hesse, the Free Theological University of Giessen and a department of the Hessian University of Police and Administration, the initial reception facility of the State of Hesse for refugees and the state office of the State Student Council of Hesse.