Madiswil is a municipality in the Oberaargau administrative district in the Canton of Bern in Switzerland. Since January 1, 2007, Gutenburg is part of the municipality. On 1 January 2011 Kleindietwil and Leimiswil were merged with the municipality of Madiswil.

Madiswil is first mentioned in 795 as Madalestwilare.

The ruins of Early Medieval ring fort at Weiherköpfli, an undated ring fort at Fuchsmatt and an undated fort at Grauenstein are the earliest evidence of settlements in Madiswil. In 795 Heribold gave his land and rights in Madiwil to the church in Rohrbach.