The Schlossbach is a river of Tyrol, Austria, a left tributary of the Inn.
The Schlossbach rises below the Reither Spitze in the municipality of Reith bei Seefeld and flows in a north to south direction. After around it collects the river Grieskarbach from the left. In its upper reaches is a gorge, the Schlossbachklamm (location: ). This is traversed at a height of by the Schlossbach Bridge which carries the track of the Mittenwald Railway. The railway bridge is a , trussed arch structure made of steel and a popular photograph subject.
After emerging from the narrow gorge into the Inn valley, the Schlossbach flows through Zirl and empties into the Inn southwest of the village. Together with the Ehnbach further east, it has pushed the Inn southwards and piled up the alluvial fan on which Zirl has been built.