Oeschinen Lake (German: Oeschinensee) is a lake in the Bernese Oberland, Switzerland, 4 km east of Kandersteg in the Oeschinen valley. At an elevation of 1,578 m, it has a surface area of 1.1147 km². Its maximum depth is 56 m.
The lake is fed through a series of mountain creeks and drains underground. The water then re-surfaces as the Oeschibach. Part of it is captured for electricity production and as water supply for Kandersteg.
In observations from 1931 to 1965, the elevation of the lake surface varied between 1,566.09 m and 1,581.9 m. The average seasonal variation was 12.2 m (September/April).
The lake is generally frozen during five months, from December to May.
Fish in the lake include arctic char (Seesaibling), lake trout (Kanadische Seeforelle), rainbow trout (Regenbogenforelle). From January to March, ice fishing is popular.
A chair lift from Kandersteg leads to Oeschinen, 20 minutes by foot from the lake.
Since 2007 the lake is part of the Jungfrau-Aletsch-Bietschhorn UNESCO World Heritage Site.