The Kaiserstuhl (German: [ˈkaɪzɐʃtuːl] ^ⓘ, lit. "Emperor’s Chair") is a range of hills in the state of Baden-Württemberg in southwest Germany with a maximum height of 556.6 metres (1,826 ft). It is of volcanic origin and located in the southwest of the state in the counties of Emmendingen and Breisgau-Hochschwarzwald. In terms of natural regions it is considered to be a part of the Upper Rhine Plain.

The name "Kaiserstuhl" is believed to refer to King Otto III, who held court near Sasbach on 22 December 994. From then on, the whole hill range was called the Königsstuhl – the King's Chair. In May 996, Otto III was crowned Emperor and the King's Chair eventually became the Emperor's Chair – "Kaiserstuhl". Reliable sources mention the name Kaiserstuhl only as early as 1304 and historians thus suppose that the term Kaiserstuhl was not coined until the 13th century.

The Kaiserstuhl is situated in South Baden, mainly in Breisgau-Hochschwarzwald county or district. However, the smaller northern part belongs to Emmendingen. Within the Upper Rhine Plain it is situated about 16 km northwest of the city of Freiburg, right next to the eastern bank of the Rhine and a short distance west of the Dreisam. It reaches up to 377 metres above the level of the Rhine downstream (179.5 m a.s.l.) from the weir close to Burkheim.

At its greatest extent, from the Michaelsberg near Riegel in the northeast, to the Fohrenberg, by Ihringen in the southwest, the Kaiserstuhl is about 15 km long. Its maximum width is about 12.5 km.

The hills of the Kaiserstuhl include the following (sorted by height in metres above sea level):

Towns and villages in and around the Kaiserstuhl (in alphabetical order) are:

The formation of the Kaiserstuhl volcano during the Tertiary was the climax and at the same time the end of volcanic activity in the Upper Rhine Valley Rift. Volcanism started as early as the Cretaceous Period. Volcanic landforms include heavily eroded volcanic vents. The Kaiserstuhl is the only larger volcano from this period in the rift valley. Geologically the Kaiserstuhl can be divided into two parts: the sedimentary and volcanic part. Due to these peculiarities the Kaiserstuhl has been labeled one of the most important national geotopes.

The horizontal sedimentary layers forming the eastern third of the Kaiserstuhl date back to the Jurassic and the Tertiary long before the volcanic activity. Important stratigraphic outcrops include the Hauptrogenstein (local oolite) which is found mainly near the village of Riegel and the Pechelbronner Schichten (local Tertiary layers in the South German Scarplands) near Bötzingen. During the formation of the Upper Rhine Plain this part of the Kaiserstuhl sloped less in respect to its surrounding area – and thus appears as a so-called horst. In terms of its geological structure and the sequence of its escarpments, the Kaiserstuhl is comparable to the nearby Tuniberg, Nimberg and also to the Schönberg, which is situated south of the city of Freiburg.