Oppstrynsvatn (also known as Oppstrynsvatnet, Strynevatnet, or Strynevatn) is a lake in the municipality of Stryn in Sogn og Fjordane county, Norway. It is located about 8 kilometres (5.0 mi) east of the municipal center of Stryn. The villages of Flo, Oppstryn, and Erdal are located on the shores of the lake.
The lake has an area of 22.87 square kilometres (8.83 sq mi) and is surrounded by many large mountains and glaciers. Some of the local attractions include the Jostedalsbreen nasjonalparksenter, Jostedalsbreen National Park, the mountain Skåla, and the glacier Tindefjellbreen.