Gniezno County (Polish: powiat gnieźnieński) 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 Gniezno, which lies 49 kilometres (30 mi) east of the regional capital Poznań.

The county covers an area of 1,254.34 square kilometres (484.3 sq mi).

The county is subdivided into 10 gminas (one urban, four urban-rural and five rural).