Schlüßlberg is a municipality in the district of Grieskirchen, in the Austrian state of Upper Austria. It lies in the Hausruckviertel region of the state, in the Alpine foothills north of the Alps.
The municipality is made up of a number of small villages and hamlets rather than a single compact town, a settlement pattern common to this part of Upper Austria. Its administrative seat is in the village of Schlüßlberg. The surrounding countryside is agricultural, and the area forms part of the wider Grieskirchen district, whose administrative centre is the town of Grieskirchen to the north.
Schlüßlberg is connected to the regional road network and lies within reach of the larger Upper Austrian cities of Wels and Linz. As with other municipalities in the district, local administration is carried out at the municipal level, with the district authorities based in Grieskirchen.