Linnansaari National Park () is a national park in the South Savo and Northern Savonia regions of Finland. It lies in the middle of the lake Haukivesi, a part of greater Saimaa. The National Park was established to conserve the valuable natural features of the Finnish lakeland.
On the main island there's an old croft. Slash-and-burn agriculture is still practised on its fields to conserve the old cultural landscape and the associated plant and animal species. A large part of the island is natural-state coniferous forest, with some herb-rich parts.
The critically endangered Saimaa ringed seal inhabits the park.