Flossach is a 21.9-kilometre-long (13.6 mi) river in Bavaria, Germany. It is a right tributary of the Mindel and an indirect right tributary of the Danube.

The Flossach rises near the village of Gerum, northwest of Türkheim at an elevation of 588 m (1,929 ft). It flows in a northwesterly direction through a broad valley, formed during the last glacial times. The 14.5 km (9.0 mi) long Weissbach flows parallel to the Flossach in the same valley. Approximately 900 m (3,000 ft) below the mouth of the brook Wörth, the Flossach divides into two branches. The main Flossach branch flows through the towns of Tussenhausen and Zaisertshofen; the other branch (called the Lettenbach or Lehnbachof) flows through Mattsiesmühle (north of Mattsies) and along the Mindelheim-Mattsies airfield. Just before joining the Mindel at an elevation of 522 m (1,713 ft), the Flossbach flows through the district of Günzburg and forms the border between Unterallgäu and Günzburg counties.

• Gerum (Rammingen )
• Mattsies and Mattsiesmühle (Tussenhausen )
• Tussenhausen
• Zaisertshofen (Tussenhausen )

• Salgen (located on the Eastern Mindel)
• Mörgen (Eppishausen)
• Bronnen (Salgen, located on the Eastern Mindel)
• Spöck (Kirchheim in Schwaben)
• Bronnerlehe (Salgen, located on the Eastern Mindel)
• Diepenhofen (Kirchheim in Schwaben)
• Kirchheim in Schwaben
• Dern (Kirchheim in Schwaben)
• Hasberg (Kirchheim in Schwaben, located on the Mindel)

• List of rivers of Bavaria