Ostrów County (Polish: powiat ostrowski) is a unit of territorial administration and local government (powiat) in Greater Poland Voivodeship, west-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 Ostrów Wielkopolski, which lies 100 kilometres (62 mi) south-east of the regional capital Poznań.

The county contains three other towns: Nowe Skalmierzyce, 22 km (14 mi) east of Ostrów Wielkopolski, Odolanów, 10 km (6 mi) south of Ostrów Wielkopolski, and Raszków, 8 km (5 mi) north of Ostrów Wielkopolski.

The county covers an area of 1,160.65 square kilometres (448.1 sq mi).