Theater Karlshorst, Cultural performance venue in Karlshorst, Berlin, Germany.

Theater Karlshorst is a neoclassical theater building in the Lichtenberg district with a circular floor plan and colonnaded entrance. Inside, the auditorium holds around 600 seats supported by round columns with ornamental capitals, while a curved gallery overlooks the main floor.

The Deutsches Haus with its ballroom stood here until 1947, when it was demolished except for the hall. Construction of the new theatre began on 14 February 1948; German architect Hans Schaefers took over site management from General Kriwuschenko on 1 August 1948. It opened as Haus der Offiziere on 31 July 1949 with Gorki's "Jegor Bulytschow und andere", attended by DDR president Wilhelm Pieck.

Locals called the building "Russenoper" because until the restricted zone was lifted in 1963 only Soviet military and civilian staff and their families could enter. David Oistrakh, Galina Ulanova and the Peking Opera ensemble performed here. After 1963 Germans attended concerts, film screenings and Jugendweihe ceremonies held to foster German-Soviet friendship.

The theatre hall itself has stood unused since the stage operation ended in April 2007, while the rest of the building houses the Schostakowitsch Music School Berlin-Lichtenberg since 2009 and an Italian restaurant. The entrance is on Johannes-Fest-Platz. Restoration and conversion into the KAHO cultural venue are scheduled from 2024, with reopening expected in 2026.

The preserved ballroom of the earlier Deutsches Haus was built into the 1948/49 neoclassical new building; up to 1,200 people danced there on a mirrored parquet floor. The rest of the old house, with its fairground, shooting booths and carousel, was demolished in 1947.