Gottorf Castle is a castle and estate in the city of Schleswig, Schleswig-Holstein, Germany. It is one of the most important secular buildings in Schleswig-Holstein, and has been rebuilt and expanded several times in its over eight hundred years of history, changing from a medieval castle to a Renaissance fortress to a Baroque castle.
It is the ancestral home of the Holstein-Gottorp branch of the House of Oldenburg, from which emerged in the 18th century, among other things, four Swedish kings and several Russian Emperors. It is situated on an island in the Schlei, about 40 km from the Baltic Sea.