Oppstrynsvatn (also known as Oppstrynsvatnet, Strynevatnet, or Strynevatn) is a lake in the municipality of Stryn in Vestland county, Norway.

It is located about 8 kilometres (5.0 mi) east of the village of Stryn (the administrative centre of the municipality).

The villages of Flo, Oppstryn, and Erdal are located on the shores of the lake.

The main outflow of the lake is the river Stryneelva which flows west into the Nordfjorden.

The Norwegian National Road 15 highway runs along the southern shore of the lake.