| Image Coa: | DEU Altenholz COA.svg |
| Coordinates: | 54.4°N 18°W |
| Image Plan: | Altenholz in RD.png |
| State: | Schleswig-Holstein |
| District: | Rendsburg-Eckernförde |
| Elevation: | 18 |
| Area: | 19.03 |
| Postal Code: | 24161 |
| Area Code: | 0431, 04349 |
| Licence: | RD, ECK |
| Gemeindeschlüssel: | 01 0 58 005 |
| Website: | www.altenholz.de |
| Mayor: | Carlo Ehrich |
Altenholz is a municipality in the district of Rendsburg-Eckernförde, in Schleswig-Holstein, Germany. It is situated near the Baltic Sea coast, approximately 20km (10miles) southeast of Eckernförde, and 9km (06miles) north of Kiel.