Wolfenbüttel is a Kreis (district) in the southeastern part of Lower Saxony, Germany. Area 722 km², population 126,800 (2001). The capital of the district is Wolfenbüttel.
The district is located southeast of Braunschweig (Brunswick). The Oker river enters the district in the south, runs through the town of Wolfenbüttel and leaves in the northwest. The district is divided into two parts by the city of Salzgitter.
Towns in the district: Wolfenbüttel, Schöppenstedt, Hornburg.