Hallevannet is a lake in Larvik Municipality in Vestfold county, Norway. The 3.72-square-kilometre (1.44 sq mi) lake lies about 8 kilometres (5.0 mi) to the west of the town of Larvik and about 4 kilometres (2.5 mi) to the northeast of the village of Helgeroa. The European route E18 highway and the Vestfoldbanen railway line both pass along the northern end of the lake.