| Image Coa: | DEU Seester COA.svg |
| Coordinates: | 53.7167°N 43°W |
| Image Plan: | Seester in PI.svg |
| State: | Schleswig-Holstein |
| District: | Pinneberg |
| Amt: | Elmshorn-Land |
| Elevation: | 7 |
| Area: | 11.57 |
| Postal Code: | 25370 |
| Area Code: | 04125 (04121, 04122) |
| Licence: | PI |
| Gemeindeschlüssel: | 01 0 56 033 |
| Website: | www.elmshorn- land.de |
| Mayor: | Claus Hell |
| Party: | CDU |
Seester (pronounced "sister") is a municipality in the district of Pinneberg, in Schleswig-Holstein, Germany.