Koło County (Polish: powiat kolski) 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 in 1998.

Its administrative seat and largest town is Koło, which lies 119 kilometres (74 mi) east of the regional capital Poznań.

The county covers an area of 1,011.03 square kilometres (390.4 sq mi).

Unit formed in Kalisz Governorate in 1867, since 1918 in the Second Polish Republic, German Landkreis Warthbrücken during World War II, later in Polish People's Republic, dissolved in 1975, reconstructed in 1998.