Bannalpsee is a reservoir in the municipality of Wolfenschiessen in the Swiss canton of Nidwalden.
The reservoir's surface area is . The construction of the reservoir was decided in 1934 and completed in 1937. The reservoir is operated by Elektrizitätswerk Nidwalden.
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 LuzernâÂÂStansâÂÂEngelberg railway line.