Tremsbüttel Castle, Manor house in Tremsbüttel, Germany.

Tremsbüttel Castle is a manor house in Tremsbüttel, Schleswig-Holstein, built 1894–1895 to a design by Berlin architect Hans Grisebach. The two-storey historicist building mixes Neorenaissance and Jugendstil elements, with ornamental gables, dormers and a donjon-like tower with a steep Gothic-style roof above the entrance portal. Inside, fixed wood panelling and stucco combine Renaissance and Baroque forms with floral Jugendstil motifs.

A 13th-century water castle of the von Wedel family stood here; the site is first documented in 1302 as Tremetesbotle. From 1544 the Schleswig-Holstein dukes used it as a hunting seat. Around 1780 Count Christian zu Stolberg-Stolberg had a classical manor built, damaged by a fire in 1851. The Hasenclever family had Hans Grisebach build the present house in 1894-1895.

The name Tremsbüttel comes from the knightly family von Wedel, who settled here in the 13th century and took the place name as their own; the earliest written record, from 1302, names it Tremetesbotle. Around 1780 the estate administrator Christian zu Stolberg-Stolberg received Matthias Claudius, Friedrich Gottlieb Klopstock and Wilhelm von Humboldt here. In June 1966 the Beatles stayed overnight during their only German tour.

The building is not open to the public: after the hotel closed in 2020, a private psychiatric clinic opened in April 2023 and filed for insolvency on 2 February 2024. The roughly four-hectare park around the house survived the parcelling of the estate after 1939. Visitors view the facade and park from outside.

The 1894–95 house was fitted with electricity when new, an unusual luxury for a country estate of the period. Its architect was Hans Grisebach of Berlin. Guests at the later hotel included Sophia Loren, the Beatles, the Rolling Stones, Leonard Bernstein and Klaus Kinski.