The Geisel valley (German: Geiseltal) is a valley in Saxony-Anhalt, Germany, situated west of Merseburg, Saalekreis district. It is named after the River Geisel which rises in Mücheln and is a tributary of the Saale, just under 25 km long. Its main settlements are Braunsbedra and Mücheln, which in future will merge into the 'collective municipality' of Geiseltal.
The Geisel valley was quarried for coal from the 17th century until 1994.
The valley is notable for its fossil record. It has yielded many important specimens of the Eocene including Propalaeotherium, Godinotia, Lophiodon, Oxyaenoides, Asiatosuchus, Geoemyda, Trogulidae and Psiloptera. It is also the site of a notable Bronze Age deposit, known as the Frankleben hoard.