Wolfenbüttel is a town in Lower Saxony, Germany. It is located on the Oker river, just a few kilometres south of Brunswick (Braunschweig). Current population: 53,000

It is not known when Wolfenbüttel was founded, but it was first mentioned in 1118 as the water castle Wulferisbutle. The first settlement was probably restricted to a tiny islet in the Oker river.

thumb|right|The house Lessing lived in during his years in Wolfenbüttel Wolfenbüttel became the residence of the dukes of Brunswick in 1432. Over the following three centuries it grew to be a center of the arts, and personages such as Michael Praetorius, Gottfried Leibniz, and Gotthold Ephraim Lessing lived there. Though the ducal court eventually moved to Brunswick in 1753 and Wolfenbüttel subsequently lost in importance, the baroque Schloss (castle) remains. Today part of the building is used as a school, and the former state apartments are open to the public as a museum.

thumb|right|The Herzog August Bibliothek Wolfenbüttel's Herzog August Bibliothek, the ducal library, has one of the largest and best-known collections of ancient books in the world. It is especially rich in bibles, incunabula, and books of the Reformation period, with some 10,000 manuscripts. It was founded in 1572 and rehoused in an interpretation of the Pantheon in 1723, built facing the castle; the present library building was constructed in 1886. Leibniz and Lessing worked in this library, Lessing as librarian. The Codex Carolinus in the library is one of the few remaining texts in Gothic.

The Battle of Wolfenbüttel during the Thirty Years' War was fought here in June 1641, when the Swedes under Wrangel and the Count of Königsmark defeated the Austrians under the Archduke Leopold of Habsburg.

Today Wolfenbüttel is smaller than the neighbouring cities of Brunswick, Salzgitter, and Wolfsburg, but because it was largely undamaged by the war it is rich in half-timber buildings, many dating several centuries back, and still retains its historical character.

Wolfenbüttel is home of several departments of the University of Applied Sciences Braunschweig/Wolfenbüttel and well as the de:Lessing-Akademie, an organization for the study of Lessing's works, and the Niedersächsische Staatsarchiv, the state archives of Lower Saxony.

The herb liqueur Jägermeister is a also specialty of Wolfenbüttel.