| Image Coa: | Wappen Untermarchtal.svg |
| Coordinates: | 48.2394°N 9.6103°W |
| Image Plan: | Untermarchtal in UL.svg |
| State: | Baden-Württemberg |
| Region: | Tübingen |
| District: | Alb-Donau-Kreis |
| Elevation: | 506 |
| Area: | 5.61 |
| Postal Code: | 89617 |
| Area Code: | 07393 |
| Licence: | UL |
| Gemeindeschlüssel: | 08 4 25 123 |
| Mayor: | Bernhard Ritzler |
| Leader Term: | 2016 - 24 |
Untermarchtal is a municipality in the district of Alb-Donau in Baden-Württemberg in Germany.