Deizisau is a town situated in the district of Esslingen within the state of Baden-Württemberg in southern Germany. It is located approximately 20 kilometers southeast of Stuttgart, the capital of the state, and lies between the towns of Plochingen and Esslingen am Neckar.
The town belongs to the Stuttgart Metropolitan Region and was part of the Stuttgart Region until 1992, when it was known as the Region Mittlerer Neckar. Geographically, the river Neckar flows through Deizisau.