| Sępólno County | |
| Native Name: | Powiat sępoleński |
| Settlement Type: | County |
| Total Type: | Total |
| Subdivision Type: | Country |
| Subdivision Type1: | Voivodeship |
| Subdivision Name1: | Kuyavian-Pomeranian |
| Area Total Km2: | 790.86 |
| Population Total: | 41055[1] |
| Population As Of: | 2019 |
| Population Density Km2: | auto |
| Population Urban: | 17431 |
| Population Blank1 Title: | Rural |
| Population Blank1: | 23624 |
| Coor Pinpoint: | Sępólno Krajeńskie |
| Coordinates: | 53.45°N 17.53°W |
| Seat: | Sępólno Krajeńskie |
| Parts Type: | Gminas |
| Parts: | Total 4 |
| P1: | Gmina Kamień Krajeński |
| P2: | Gmina Sępólno Krajeńskie |
| P3: | Gmina Sośno |
| P4: | Gmina Więcbork |
| Blank Name: | Car plates |
| Blank Info: | CSE |
| Website: | http://www.powiat-sepolno.pl |
Sępólno County (pl|powiat sępoleński) is a unit of territorial administration and local government (powiat) in Kuyavian-Pomeranian Voivodeship, north-central Poland. It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat and largest town is Sępólno Krajeńskie, which lies 490NaN0 north-west of Bydgoszcz and 860NaN0 north-west of Toruń. The county also contains the towns of Więcbork, lying 110NaN0 south of Sępólno Krajeńskie, and Kamień Krajeński, 100NaN0 north of Sępólno Krajeńskie.
The county covers an area of 790.86km2. As of 2019 its total population is 41,055, out of which the population of Sępólno Krajeńskie is 9,091, that of Więcbork is 5,950, that of Kamień Krajeński is 2,390, and the rural population is 23,624.
Sępólno County is bordered by Człuchów County and Chojnice County to the north, Tuchola County to the north-east, Bydgoszcz County to the south-east, Nakło County to the south, and Piła County and Złotów County to the west.
The county is subdivided into four gminas (three urban-rural and one rural). These are listed in the following table, in descending order of population.
| Gmina | Type | Area (km2) | Population (2019) | Seat |
| Gmina Sępólno Krajeńskie | urban-rural | 229.2 | 15,773 | Sępólno Krajeńskie |
| Gmina Więcbork | urban-rural | 235.7 | 13,333 | Więcbork |
| Gmina Kamień Krajeński | urban-rural | 163.2 | 6,946 | Kamień Krajeński |
| Gmina Sośno | rural | 162.8 | 5,003 | Sośno |