| Olsztyn County | |
| Native Name: | Powiat olsztyński |
| Settlement Type: | County |
| Total Type: | Total |
| Image Map1: | olsztynski.png |
| Map Caption1: | Division into gminas |
| Subdivision Type: | Country |
| Subdivision Type1: | Voivodeship |
| Subdivision Name1: | Warmian-Masurian |
| Area Total Km2: | 2840.29 |
| Population Total: | 113529 |
| Population As Of: | 2006 |
| Population Density Km2: | auto |
| Population Urban: | 39205 |
| Population Blank1 Title: | Rural |
| Population Blank1: | 74324 |
| Coor Pinpoint: | Olsztyn |
| Coordinates: | 53.7833°N 50°W |
| Seat: | Olsztyn |
| Parts Type: | Gminas |
| Parts: | Total 12 |
| P1: | Gmina Barczewo |
| P2: | Gmina Biskupiec |
| P3: | Gmina Dobre Miasto |
| P4: | Gmina Dywity |
| P5: | Gmina Gietrzwałd |
| P6: | Gmina Jeziorany |
| P7: | Gmina Jonkowo |
| P8: | Gmina Kolno |
| P9: | Gmina Olsztynek |
| P10: | Gmina Purda |
| P11: | Gmina Stawiguda |
| P12: | Gmina Świątki |
| Blank Name: | Car plates |
| Blank Info: | NOL |
| Website: | http://www.powiat-olsztynski.pl |
Olsztyn County (Polish: powiat olsztyński) is a unit of territorial administration and local government (powiat) in Warmian-Masurian Voivodeship, northern Poland. It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat is the city of Olsztyn, although the city is not part of the county (it constitutes a separate city county). The county contains five towns: Dobre Miasto, 240NaN0 north of Olsztyn, Biskupiec, 310NaN0 east of Olsztyn, Olsztynek, 270NaN0 south-west of Olsztyn, Barczewo, 140NaN0 north-east of Olsztyn, and Jeziorany, 260NaN0 north-east of Olsztyn.
The county covers an area of 2840.29km2. As of 2006 its total population is 113,529, out of which the population of Dobre Miasto is 10,489, that of Biskupiec is 10,348, that of Olsztynek is 7,591, that of Barczewo is 7,401, that of Jeziorany is 3,376, and the rural population is 74,324.
Apart from the city of Olsztyn, Olsztyn County is also bordered by Lidzbark County and Bartoszyce County to the north, Kętrzyn County and Mrągowo County to the east, Szczytno County to the south-east, Nidzica County to the south, and Ostróda County to the west.
The county is subdivided into 12 gminas (five urban-rural and seven rural). These are listed in the following table, in descending order of population.
| Gmina | Type | Area (km2) | Population (2006) | Seat |
| Gmina Biskupiec | urban-rural | 290.4 | 19,018 | Biskupiec |
| Gmina Barczewo | urban-rural | 319.9 | 16,525 | Barczewo |
| Gmina Dobre Miasto | urban-rural | 258.7 | 15,920 | Dobre Miasto |
| Gmina Olsztynek | urban-rural | 372.0 | 13,666 | Olsztynek |
| Gmina Dywity | rural | 160.7 | 9,148 | Dywity |
| Gmina Jeziorany | urban-rural | 213.5 | 8,140 | Jeziorany |
| Gmina Purda | rural | 318.2 | 7,268 | Purda |
| Gmina Jonkowo | rural | 168.2 | 5,719 | Jonkowo |
| Gmina Gietrzwałd | rural | 174.1 | 5,315 | Gietrzwałd |
| Gmina Stawiguda | rural | 222.5 | 5,134 | Stawiguda |
| Gmina Świątki | rural | 163.8 | 4,234 | Świątki |
| Gmina Kolno | rural | 178.3 | 3,442 | Kolno |