'Ägerisee' (or ''Lake Aegeri'') is a glacial lake in the Canton of Zug, Switzerland. The two municipalities along its shore are Oberägeri and Unterägeri. The main tributary is the ''Hüribach''; the Lorze river drains the Ägerisee. Since 1992 the lake is used as a water reservoir.
The Battle of Morgarten took place in 1315 on the shores of the Ägerisee.