Hessisches Staatstheater Wiesbaden, Opera house and theater in Wiesbaden, Germany.

The Hessisches Staatstheater Wiesbaden is a Baroque Revival theatre built 1892–1894 by the Viennese office Fellner & Helmer. Its pale stone front carries a columned portico with a triangular pediment, dark rounded domed roofs sit above, and two symmetrical wings with rows of windows extend to either side. A wide curved stair leads up from lawn and trees; behind, a second columned front faces a paved plaza with a balustrade and lines of trees.

Built 1892–1894 by Viennese architects Fellner & Helmer in Baroque Revival style for Emperor William II, who opened it on 16 October 1894 as the Königliches Theater. Renamed Preußisches Staatstheater in 1918 and Nassauisches Landestheater in 1932, it was hit by bombs on 3 February 1945, losing the portico, box office hall and auditorium ceiling. Reopened in 1947 under the State of Hesse, the auditorium was restored 1975–1978.

Since 1896 the theatre has hosted the Internationale Maifestspiele in May, founded after the Bayreuth Festival. A biennial festival, "Neue Stücke aus Europa", has presented new European plays in their original language with simultaneous translation since 2004, and the Junges Staatstheater performs for children and young people, working with schools on Schultheatertage.

The main entrance sits in the centre of the Theaterkolonnade, which faces the Kurhauskolonnade across the Bowling Green; the rear facade, reached from the large outer door, opens directly onto the stage. The historic house holds three stages, with the separate Wartburg venue on Schwalbacher Straße added in 2003. The auditorium was restored from 1975 to 1978 and the Kleines Haus now seats 285.

The building was designed by Viennese architects Fellner and Helmer, who created theaters following the same architectural pattern in Prague and Zurich. This connection to other European cities demonstrates how popular their design approach was in the late 1800s.