Leimiswil was until December 31, 2010, a municipality in the Oberaargau the canton of Bern in Switzerland.
The typical scattered settlement has no real village center, the former municipality include the larger hamlet basswood, Leimiswil and Linden, there are to many individual houses.
Leimiswil located in the Upper Aargau in the Swiss Mittelland.
The community is strongly influenced rural, 63 % of farms are farms.
At the community meetings from December 12, 2009 voted 124 out of 164 eligible voters present for a merger with Madiswil and Kleindietwil. Thus Leimiswil is from January 1, 2011 belong to the new municipality Madiswil.