Horrenbach-Buchen is a municipality in the administrative district of Thun in the Canton of Bern in Switzerland .

Originally the small farming villages that make up Horrenbach-Buchen were part of the Herrschaft of Heimberg under the House of Kyburg. After a failed raid on Solothurn on 11 November 1382 and the resulting Burgdorferkrieg, the Kyburgs lost most of their lands, including Horrenbach-Buchen, to Bern in 1384. Under Bernese rule it was part of the Steffisburg court under the Thun District. Religiously it was part of the parish of Steffisburg until 1693 when it joined the Schwarzenegg parish. A church was built in Buchen in 1928, which became a parish church in 1935.