Bad Waldsee (German pronunciation: [baːt ˈvaltˌzeː] ^ⓘ) is a town in Upper Swabia in Baden-Württemberg, Germany. It is part of the district of Ravensburg. It is situated 20 km south of Biberach an der Riß, and 20 km northeast of Ravensburg. The town has a historic old city with landmarks and pedestrian zone. Bad Waldsee is the district center for the Bodensee-Oberschwaben district and is the seat of the townships of Bad Waldsee, Aulendorf and Bergatreute.

Bad Waldsee is located in Upper Swabia north of the Altdofer forest. The old city is situated on an isthmus between two lakes—the Stadtsee on the east connects to Urbach through a channel in the south, and the smaller Schlosssee on the west, which empties into the Stadtsee from the direction of Pfaffenbach.

Waldsee was first documented in 926 in the Weissenburger Codex, which mentions the destruction caused by the Hungarians during their invasion of southern Germany. It says "In Walahsé a royal estate was destroyed by the heathens. All it has left is two lots of farmland, 60 carts of hay, a mill and a church." The town was granted city-rights in 1298. Authority over the city was exercised by the "Lords of Waldsee", a title the city soon sold to the Habsburg Duke of Austria. However, in 1386 the House of Habsburg pledged the city of Waldsee to the steward Johann von Waldburg.

In 1406 the pledge lordship (Pfandherrschaft) of Waldburg was renewed, when the city of Waldsee, together with the towns of Mengen, Riedlingen, Munderkingen and Saulgau, were finally sold off by the House of Habsburg. From this time these cities have been known together as the "fünf Donaustädte" (Five Danube Towns). The House of Waldburg stayed in control of the towns until Napoleon established a new European order through war and politics, which made Waldsee part of the Kingdom of Württemberg in 1806. In 1807 Waldsee was elevated the status of township, and the city grew in prominence during this period.

In 1918 the nickel and copper coins became scarce because of the First World War. That is why many communities were forced to mint their own coins. The council of Waldsee consulted on March 13, 1918 the minting of their own coins. It was decided to issue coins in sizes of 50 Pfennig, 10 Pfennig and 5 Pfennig. They could be exchanged until May 1, 1922.

In 1923, when inflation reached its peak, the city printed its own money in bills. On August 26, 1923, the local council decided to issue certificates worth 500,000, 1 million Mark and 2 million marks. Later it was decided to print more certificates with the values five million to ten trillion. The back of the bills of five million to twenty billion showed the "Iron Man", the Steward of Waldburg.

Waldsee held the status of township until 1938, when the Nazi Government dissolved the townships and Waldsee became part of the new Biberach and Ravensburg County. In 1942 Erich Bachem founded Bachem-Werke GmbH in the town. The company built and tested the Bachem Ba 349 rocket plane in Waldsee.^{[citation needed]}

During the economic restructuring after the War, the city opened its first mud bath spa in 1950. With the construction of more spas, the city obtained the designation "Moorheilbad", awarded to spa towns with mud thought to have curative properties.^{[by whom?]} In 1974 the city was designated as "Kneippkurort", awarded to certain towns with water thought to have curative properties.^{[by whom?]}