Zweisimmen is a municipality in the Obersimmental-Saanen administrative district in the canton of Bern in Switzerland. The village church and its rectory, the ruins of Oberer Mannenberg Castle and the ruins of Unterer Mannenberg Castle are listed as Swiss heritage site of national significance.

Zweisimmen is first mentioned in 1228 as Duessimenes. In 1257 it was mentioned as Zweinlixhenun.

The oldest trace of a settlement in the area are some scattered mesolithic artifacts from Mannenberg-Riedli. The remains of a Roman era settlement were found at Mannried.

During the Middle Ages a significant trade route over the Alps to Valais and Lake Geneva passed through the Zweisimmen region. A number of farming villages probably existed in the area during the Middle Ages. In the 13th and 14th centuries, local nobles built several castles, Upper Mannenberg and Lower Mannenberg, Reichenstein-Terenstein, Blankenburg and Steinegg Castles, to protect and collect taxes from the roads. The villages and castles passed through several noble families until 1378 when the Lord of Düdingen sold the lands to Fribourg following an uprising. After the Battle of Sempach in 1386, Bern conquered the Simmen river valley (Simmental) and acquired Zweisimmen. The Bernese administrator over the upper Simmen valley was installed at Blankenburg Castle. Reichenstein-Terenstein Castle and estates were acquired by the Bubenberg family in 1456, and sold to Bern in 1493. Blankenburg village remained the political center of the Obersimmental district through the 1798 French invasion and the Act of Mediation in 1803. It remained the capital until the district was dissolved in 2009.

The village St. Mary's Church was probably built in the Early or High Middle Ages. It first appears in a historical record in 1228. It was rebuilt and expanded several times in the 13th to 15th centuries. The murals and stained glass date from the same period. The carved wooden ceiling was added around 1456. An ossuary was built under the church in 1481. In 1528 Bern adopted the new faith of the Protestant Reformation and spread it throughout its land. Zweisimmen, along with much of the Bernese Oberland initially resisted the new faith, but were forced to convert in the same year. The church was secularized and used for storage and meetings. In 1866 it became the Blankenburg village school.

During the Middle Ages Zweisimmen grew into a local center for trade and government. In 1644 the annual fair was moved to Zweisimmen and brought cattle and cheese buyers from Italy and Germany to the municipality. In the 1750s a trade route from Thun to Montreux was built into Zweisimmen. The Simmental road was built from Saanen into the Simmen valley in 1816-45. The new road brought additional trade and eventually tourists to the municipality. A hotel was built in 1881. The completion of the Spiez-Zweisimmen-Montreux railroad in 1905 opened the villages up to many additional tourists. The hotel became a spa and resort in 1912 and included winter sports in 1920. The municipal tourism industry was devastated by the Great Depression and World War II. However, it began to recover in the 1950s with many new cable cars and ski lifts. Zweisimmen cooperated with the neighboring tourist municipalities of Gstaad, Lenk im Simmental and Adelboden to build extensive ski resorts along with an airfield.