| Oldenswort Oldensvort | |
| Image Coa: | DEU Oldenswort COA.svg |
| Coordinates: | 54.3667°N 63°W |
| Image Plan: | Oldenswort in NF.PNG |
| State: | Schleswig-Holstein |
| District: | Nordfriesland |
| Amt: | Eiderstedt |
| Elevation: | 0 |
| Area: | 45.84 |
| Postal Code: | 25870 |
| Area Code: | 04864 |
| Licence: | NF |
| Gemeindeschlüssel: | 01 0 54 095 |
| Mayor: | Frank-Michael Tranzer |
| Party: | SPD |
Oldenswort (da|Oldensvort) is a municipality in the district of Nordfriesland, in Schleswig-Holstein, Germany, next to the river Eider.
The earliest atheist known by name in modern Europe, Matthias Knutzen, was born here sometime in early 1646. The founder of German sociology, Ferdinand Tönnies (1855-1936), was born here. A memorial of him was unveiled in 1990.[1]