Pyhäjoki is a municipality of Finland.
It is located in the province of Oulu and is part of the Northern Ostrobothnia region. The municipality has a population of 3,554 (2003) and covers an area of 546.14 km² of which 5.83 km² is water. The population density is 6.6 inhabitants per km².
The municipality is unilingually Finnish.
