Ortenaukreis (Low Alemannic: Ortenaukrais; French: Arrondissement de l'Ortenau) is a Landkreis (district) in the west of Baden-Württemberg, Germany. Neighboring districts are (clockwise from north) Rastatt, Freudenstadt, Rottweil, Schwarzwald-Baar and Emmendingen. To the west it borders the French Bas-Rhin département.

The district was created in 1973 by merging the districts of Kehl, Lahr, Offenburg, Wolfach and the southern part of the district of Bühl.

The western part of the district is located in the Upper Rhine Valley, the eastern part belongs to the northern Black Forest. The highest elevation of the district, the Hornisgrinde (1164 m), is located in the north-east of the district.