| Image Coa: | DEU Alt Bennebek COA.svg |
| Coordinates: | 54.3833°N 35°W |
| Image Plan: | Alt Bennebek in SL.PNG |
| State: | Schleswig-Holstein |
| District: | Schleswig-Flensburg |
| Amt: | Kropp-Stapelholm |
| Elevation: | 2 |
| Area: | 14.09 |
| Postal Code: | 24848 |
| Area Code: | 04624 |
| Licence: | SL |
| Gemeindeschlüssel: | 01 0 59 001 |
| Website: | www.kropp.de |
| Mayor: | Armin Falkenhorst |
Alt Bennebek (Danish: Gammel Bennebæk) is a municipality in Schleswig-Flensburg district, in Schleswig-Holstein, northern Germany.
Old Bennebek located about 30 km north-west of Rendsburg in the Sorgeniederung on the border between Geest and Marsch. About 15 km to the west, the highway 77 runs and 30 km west, the Federal Highway 7 of Rendsburg to Schleswig.