Seiland National Park (Norwegian: Seiland nasjonalpark or Northern Sami: Sievjju álbmotmeahcci) lies in Alta Municipality and Hammerfest Municipality in Finnmark county, Norway. The park includes the majority of the island of Seiland, the second-largest island in Finnmark after Sørøya. The park includes two glaciers: Seilandsjøkelen and Nordmannsjøkelen (the northernmost glaciers in Scandinavia). The highest point in the park is the 1,078-metre (3,537 ft) tall mountain Seilandstuva. The 316-square-kilometre (122 sq mi) park was established on 8 December 2006. The 9.6 square kilometres (3.7 sq mi) of the water inside the park's area, includes the surrounding sea and many fjords including the Nordefjorden, Sørefjorden, and Flaskefjorden.

The name of the island must be very old, from Proto-Norse *Sai-aujo ("sea-island"), and the Northern Sami language name Sievju is probably an old loan and reflection of this form. In Norse times, the name was transformed first to *Sæ-ey, and then to just *Sei. The last element land means "land" or "island" is a later addition.