Wägitalersee is a reservoir lake in the municipality of Innerthal in the Canton of Schwyz , Switzerland . It is situated in the Wägital (English: Wägi Valley). Its outflow is the Wägitaler Aa, which drains into Upper Lake Zurich at Lachen. It is surrounded by the mountains Gross Aubrig , Fluebrig , Zindlenspitz , Brünnelistock and Bockmattli.

The old village of Innerthal was flooded in 1924 when the dam Schräh was constructed. A new village was built on the current lake.