Theater Osnabrück, Art Nouveau theatre complex in Osnabrück, Germany.

Theater Osnabrück is an opera house and concert hall in the city of Osnabrück. It operates two performance venues: the Theater am Domhof with 642 seats and the emma-theater with 96 seats for different types of shows.

The building opened in 1909 and displays Art Nouveau architecture. After damage during World War II, it was reconstructed and remains part of the city's theatrical tradition that began in 1771.

The theatre's name goes back to the Stadttheater founded in 1909, and its stage curtain was a gift from the women of Osnabrück. Since 1945 the Theaterverein Osnabrück has supported the house, and since 2013 it awards the Osnabrücker Dramatikerpreis together with the theatre. Each season brings about 25 new productions, eight symphony concerts and over 700 events.

The main house is the Theater am Domhof at Domhof/Platz der Deutschen Einheit, with 585 seats plus 42 in the orchestra rows; the emma-theater in the Weststadt holds 105. Shallow steps lead up to the entrances of the sandstone building. The season brings around 25 new productions, eight symphony concerts and over 700 events.

The stage curtain that rose on 29 September 1909 for Julius Caesar was a gift from the women of Osnabrück, as was much of the building's funding. The theatre also runs OSKAR, a young people's division serving the city and district, supported by the friends' association OSKARs Freunde e. V.