Wołomin County (Polish: powiat wołomiński) is a territorial and administrative division in Masovian Voivodeship, east-central Poland.

It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998.

The administrative seat of the county and also its largest town is Wołomin, which lies 22 kilometres (14 mi) north-east of Warsaw.

The county covers an area of 955.37 square kilometres (368.9 sq mi).

The county is subdivided into 12 gminas (four urban, three urban-rural and five rural).