Herzogenbuchsee is a municipality in the Oberaargau administrative district in the Canton of Bern in Switzerland .

The population is 7055 (2011), counting the villages in the Oberaargau. The traditional name was Buchsi.

Herzogenbuchsee is built on a moraine of the Rhone Glacier. The area has been settled for at least 10,000 years, with ancient settlements around the Inkwilersee and Burgäschisee . There is also evidence of Roman buildings from approximately 200 CE near the current Reformed Church.