Fyresvatn

Infobox lake
lake_name = Fyresvatn
image_lake = Fyresvatn.jpg
caption_lake =
image_bathymetry =
caption_bathymetry =
location = Fyresdal, Telemark
coords = coord|59|06|N|8|12|E|region:NO_type:waterbody|display=inline,title
type =
inflow =
outflow = Fyreselv
catchment =
basin_countries = Norway
length =
width =
area = 49.63 km²
depth =
max-depth = 377 m
volume =
residence_time =
shore = 63.41 km
elevation = 279 m
islands =
cities =

Fyresvatn, (or Fyresvatnet), is the fifth deepest lake in Norway with a depth of 377 m.

It is located in Fyresdal municipality, part of Telemark county.

Fyresvatn belongs to the Arendal watershed, and discharges via the Fyreselv river into the Nidelva river, which flows into the Skagerak at Arendal in the county of Aust-Agder.