Steffisburg is a municipality in the administrative district of Thun in the canton of Bern in Switzerland.
Steffisburg is first mentioned in 1133 as Stevensburc. The municipality was formerly known by its French name Steffisbourg, however, that name is no longer used.
The area around Steffisburg has been inhabited since the Neolithic era and remained occupied during the Bronze Age. Traces of a Roman site were discovered in Schwäbis. Early medieval graves have been discovered at Zelgmatte and Klosterhubel. By the High Middle Ages the entire Zulgtal, including Steffisburg, was owned by the local Freiherr von Heimberg family. Under the Zähringer family, the Grafschaft of Thun expanded to include the village. When they died out in 1218 it passed to the Kyburgs, who made Steffisburg a fief for several different Ministerialis (unfree knights in the service of a feudal overlord) families. One of these families, the von Kien, built what became known as the Kleine Höchhus in the 14th century, when they administered the municipality. Today, the Kleine Höchhus is one of the oldest buildings in the municipality. Steffisburg became the center of a local court jurisdiction. Over the following years portions of the village and surrounding farms were donated to several local monasteries.