Oeschinen Lake (German: Oeschinensee) is a lake in the Bernese Oberland, Switzerland, 4 kilometres (2.5 mi) east of Kandersteg in the Oeschinen valley. At an elevation of 1,578 metres (5,177 ft), it has a surface area of 1.1147 square kilometres (0.4304 sq mi). Its maximum depth is 56 metres (184 ft).
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 metres (5,138.1 ft) and 1,581.9 metres (5,190 ft). The average seasonal variation was 12.2 metres (40 ft) (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 gondola 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.