Kellinghusen (German pronunciation: [kɛlɪŋˈhuːzən] ⓘ) is a town in the district of Steinburg in the Bundesland of Schleswig-Holstein.

The Luftkurort Kellinghusen, a health resort, is in the countryside of Holstein and a gateway to the 380-square-kilometer Aukrug Nature Park.

The slightly hilly landscape of this nature park, with a favorable climate of forests, ponds, heathland, and moorland, serves as a popular holiday destination.

The town, which has existed since the time of Charlemagne, was first known as Kellinghusen around the year 1148, as evidenced by the name "Thoto of Kerleggehusen."

During the Cold War an arsenal of nuclear weaponry of the United States Armed Forces was situated in Kellinghusen.