| Bramming–Tønder railway line | |
| Native Name: | Bramming-Tønder-banen |
| Native Name Lang: | da |
| Type: | Heavy rail |
| System: | Danish railway |
| Status: | Operational |
| Stations: | 14 |
| Open: | (–) (–) |
| Owner: | Banedanmark |
| Operator: | GoCollective |
| Character: | Passenger trains Freight trains |
| Linelength Km: | 67.9 |
| Linelength Mi: | 42.2 |
| Tracks: | Single track |
| Linenumber: | 30 |
| Speed: | 100 km/h (–) 60 km/h (–German border |
| Map Name: | The Bramming–Tønder railway line |
| Map State: | uncollapsed |
The Bramming–Tønder railway line (da|Bramming-Tønder-banen) is a 67.9km (42.2miles) long railway line in Denmark which runs through the historical region of Southern Jutland between and the German border just south of . The standard gauge railway line is single track and unelectrified.
The railway line is historically a part of the Marsh Railway (de|Marschbahn), the through route along the west coast of Schleswig-Holstein from the city of Elmshorn to Bramming. Today, the line continues to the German border just south of, where it connects to the rump section of the Marsh railway and the German railway network.