Thun is a town and a municipality in the administrative district of Thun in the canton of Bern in Switzerland. It is located where the Aare flows out of Lake Thun, 30 kilometres southeast of Bern.
As of December 2018 the municipality has almost about 45,000 inhabitants and around 80,000 live in the agglomeration.
Besides tourism, machine and precision instrument engineering, the largest garrison in the country, the food industry, armaments and publishing are of economic importance to Thun.
The official language of Thun is German, but the main spoken language is the local variant of the Alemannic Swiss German dialect.