Leszno County (Polish: powiat leszczyński) 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.

The county covers an area of 804.65 square kilometres (310.7 sq mi).

The county is subdivided into seven gminas (two urban-rural and five rural).

These are listed in the following table, in descending order of population.