Saint-Julien-des-Landes () is a commune in the Vendée department, in the Pays de la Loire region of western France.
The commune's municipal territory extends to 2,845 hectares. The altitude is 51 metres, and fluctuates from 7m to 66m.
In the north, it is bordered by the river Jaunay.
The commune is host to two large campsites: Camping Chateau La Forêt within the village and la garangeoire just outside.