Pajęczno County (Polish: powiat pajęczański) is a unit of territorial administration and local government (powiat) in Łódź Voivodeship, 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 Pajęczno, which lies 78 kilometres (48 mi) south-west of the regional capital Łódź. The only other town in the county is Działoszyn, lying 10 km (6 mi) west of Pajęczno.
The county covers an area of 804.14 square kilometres (310.5 sq mi). As of 2006 its total population is 53,395, out of which the population of Pajęczno is 6,674, that of Działoszyn is 6,276, and the rural population is 40,445.