Teatro El Círculo, Opera house and theatre in Rosario, Argentina.

Teatro El Círculo is an opera house and theatre in Rosario, Argentina, situated at the corner of Laprida and Mendoza Streets with seating for around 1,450 people. The building was designed by German engineer George Goldammer and combines architectural influences from several European styles, visible both on the facade and inside the main hall.

Construction began in 1888 for the society La Ópera, but the company went bankrupt and the unfinished shell became known as the "Cueva de los Ladrones". Emilio Schiffner bought it and resumed work to plans by engineer George Goldammer, and the theatre opened on 7 June 1904 with Verdi's Otello. Saved from demolition in 1943 by the Asociación Cultural El Círculo, it is a National Historical Monument of Argentina.

The theatre's name comes from the Asociación Cultural El Círculo, a private institution founded in 1912 that acquired the building in 1943 and still owns it. Since 2006 it has operated as a cultural centre, housing the Estudio de Comedias Musicales, the Academia de Ballet Clásico Ruso and the Ópera de Rosario. Its stage curtain, designed by Giuseppe Carmignani, depicts Greek mythological figures similar to those in the Teatro Regio di Parma.

The theatre stands at the corner of Laprida and Mendoza Streets, near the historic centre. For the 2004 centenary the surrounding streets were paved with cobblestones and fitted with old-style lampposts, so the corner now reads as a small plaza. The main hall seats 1,450 people across five levels, and the building also holds two lecture and theatre rooms, an exhibition room and a small museum on the ground floor.

The vaults beneath the theatre were converted into the Museum of Sacred Art in 1940, the same year the city was actively considering demolition of the building. The museum holds original plaster works and sculptures by Eduardo Barnes. The theatre's stage curtain, painted by Giuseppe Carmignani with Greek mythological figures, was modelled on the one at the Teatro Regio di Parma.