Bannalpsee is a reservoir in the municipality of Wolfenschiessen in the Swiss canton of Nidwalden.

[1] The reservoir's surface area is 16 hectares (40 acres).

The construction of the reservoir was decided in 1934 and completed in 1937.

The reservoir is operated by Elektrizitätswerk Nidwalden.

[2] The lake can be reached by a cable car from Oberrickenbach, which in turn is linked by post bus service to Wolfenschiessen station on the Luzern–Stans–Engelberg railway line.