| Conventional Long Name: | Olsztyn District |
| Native Name: | Okręg olsztyński (Polish) |
| Subdivision: | District |
| Nation: | Duchy of Wieluń |
| Membership Title1: | Country |
| Membership1: | Duchy of Wieluń |
| Year Start: | c. 1378 |
| Date End: | 1391 |
| Event End: | Conquest of Duchy of Wieluń by Kingdom of Poland |
| P1: | Wieluń Land |
| Flag P1: | Grunwald Velumensis Terra banderium.svg |
| S1: | Kingdom of Poland (1385–1569)Kingdom of Poland |
| Flag S1: | Flag of the Kingdom of Poland.svg |
| Border S1: | no |
| Capital: | Olsztyn |
Olsztyn District was a district within the Duchy of Wieluń. Its capital was Olsztyn. It was formed around 1378 from Wieluń Land and existed until 1391 when duchy was conquered by Kingdom of Poland.[1] The city serves as a trade centre, with major rail and road connections, for the lake district. The Museum of Warmia and Mazury and a university are located in Olsztyn.