Wejherowo County (Kashubian: Wejrowsczi kréz, Polish: powiat wejherowski) is a unit of territorial administration and local government (powiat) in Pomeranian Voivodeship, northern Poland, on the Baltic coast.

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 Wejherowo, which lies 36 kilometres (22 mi) north-west of the regional capital Gdańsk.

The county also contains the towns of Rumia, lying 11 km (7 mi) east of Wejherowo, and Reda, 7 km (4 mi) east of Wejherowo.

The county covers an area of 1,279.84 square kilometres (494.1 sq mi).