Hartevatnet or Hartevatn is a lake in the municipality of Bykle in Agder county, Norway.

It is located along the river Otra, on the south side of the village of Hovden.

The lake is a good fishing spot and contains many brown trout.

The Norwegian National Road 9 runs along the eastern shore of the lake.

It was formed by the building of a hydro-electric dam on the river Otra.