Laduviken (Swedish: Barn Bay) is a lake in Norra Djurgården, a semi-rural area in north-eastern Stockholm, Sweden, forming part of the Royal National City Park.

West of the lake, the buildings of the Stockholm University take up some 20 per cent of the surface and a few roads, a traffic route, the suburban railway Roslagsbanan, and the subterranean metro passes through the area.

A tiny river guides the outflow east to the bay Husarviken which is part of the strait Lilla Värtan.

Generally the lake is considered as in good health with low levels of most metals and organic compounds, even though presence of hydrogen sulphide has been recorded relatively frequently, levels of copper in top sediments did increase during the 1990s, and analysis's of subsoil water in 1997 showed signs of environmental contamination.

[3] Mallard and great crested grebe are breeding in the lake, just like are occasionally common moorhen and Canada goose (introduced in Sweden in the 1930s).

Even though reed have been cleared to attract waders, as a locale for birs, the lake hasn't met expectations much due to neglected attention of the canals and islands.