Westzaan is a town in the Dutch province of North Holland. It is a part of the municipality of Zaanstad, and lies about 13 km northeast of Haarlem. It is located west of Zaandam, Koog aan de Zaan and Zaandijk, southwest of Wormer, southeast of Krommenie and south and southeast of Assendelft.
Westzaan was a separate municipality until 1974, when it became a part of Zaanstad.
In 2001, the town of Westzaan had 2130 inhabitants. The built-up area of the town was 0.34 km², and contained 834 residences. The statistical district "Westzaan", which covers the village and the surrounding countryside, has a population of around 4580. Westzaan has the only wind powered paper mill in the world.