| Tannbach | |
| Source1 Location: | east of Gefell-Gebertsreuth |
| Source1 Coordinates: | 50.4365°N 11.9035°W |
| Source1 Elevation: | 620m (2,030feet) NN |
| Mouth Location: | Saale (between Joditz and Hirschberg) |
| Mouth Coordinates: | 50.3939°N 11.8349°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | States |
| Subdivision Name2: | Bavaria and Thuringia |
| Length: | 8.7km (05.4miles) |
| Mouth Elevation: | 445m (1,460feet) NN |
| Tributaries Left: | Kupferbach |
Tannbach is a brook that is 8.7km (05.4miles) long in north-east Bavaria and southern Thuringia, Germany.
The source is located east of Gefell in the Saale-Orla-Kreis district in Thuringia. Initially it flows south through Gebersreuth, a district of Gefell, before reaching Mödlareuth. During the Cold War the little brook marked the border between West and East Germany and divided the little village into two parts. After Mödlareuth it flows in south-westerly direction before it joins the Saale as right tributary.