Linnansaari National Park (Finnish: Linnansaaren kansallispuisto) is a national park located in the South Savo and Northern Savonia regions of Finland. It is situated in the center of Lake Haukivesi, which is part of the larger Saimaa lake system. The National Park was created to protect the important natural features of Finland's lake region.

On the main island, there is an old farm. Farmers still use a traditional method called slash-and-burn agriculture on the island's fields to help preserve the historical landscape and the plants and animals that live there. Much of the island is covered with natural coniferous forests, and some areas have rich plant life.

The critically endangered Saimaa ringed seal lives in the park.