Alavieska 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 2,518 and covers an area of 253.02 square kilometres (97.69 sq mi) of which 1.66 km2 (0.64 sq mi) is water. The population density is 10.02 inhabitants per square kilometre (26.0/sq mi). Neighbouring municipalities are Kalajoki, Merijärvi, Oulainen and Ylivieska.
The municipality is unilingually Finnish.