| Lachen | |
| Image Coa: | Wappen Lachen.svg |
| Coordinates: | 47.95°N 24°W |
| Image Plan: | Lachen in MN.svg |
| State: | Bayern |
| Region: | Schwaben |
| District: | Unterallgäu |
| Verwaltungsgemeinschaft: | Memmingerberg |
| Elevation: | 651 |
| Area: | 13.34 |
| Postal Code: | 87760 |
| Area Code: | 08331, 08332 |
| Licence: | MN |
| Gemeindeschlüssel: | 09 7 78 162 |
| Divisions: | 7 |
| Website: | www.gemeinde-lachen.de |
| Mayor: | Josef Diebolder[1] |
| Leader Term: | 2020 - 26 |
| Party: | FW |
Lachen is a municipality in the district of Unterallgäu in Bavaria, Germany. The town has a municipal association with Memmingerberg.