The Schleswig-Holstein Wadden Sea National Park is a national park in the Schleswig-Holstein area of the German Wadden Sea. It was founded by the Parliament of Schleswig-Holstein on 1 October 1985 by the National Park Act of 22 July 1985 and expanded significantly in 1999. Together with the Lower Saxon Wadden Sea National Park, the Hamburg Wadden Sea National Park and those parts of Elbe estuary which are not nature reserves, it forms the German part of the Wadden Sea.

The Wadden Sea is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of low-lying Frisian Islands, forming a shallow body of water with tidal flats and wetlands. It has a high biological diversity and is an important area for both breeding and migrating birds. In 2009, the Dutch and German parts of the Wadden Sea were inscribed on UNESCO's World Heritage List and the Danish part was added in June 2014.