The Museum Ostwall (known as Museum am Ostwall until 2010) is a museum of modern and contemporary art in Dortmund, Germany. It was founded in the late 1940s, and has been located in the Dortmund U-Tower since 2010. The collection includes paintings, sculptures, objects and photographs from the 20th century, plus over 2,500 graphics, spanning Expressionism through classic modern art to the present day.
The museum's original location, from 1947 until 2009, was a building on the Ostwall (a road in central Dortmund following the old city walls), including a small sculpture garden. The previous building on the site had been the Museum für Kunst und Kulturgeschichte (MKK), a municipal art collection, from 1911 until its destruction in World War II; before 1911 it housed the old Westphalia Mining Authority.
A gradual rebuilding, using construction materials from the ruins of the MKK, began in the late 1940s. The first exhibition at the Museum am Ostwall was held in 1949 – making it one of Germany's first post-war museums of 20th-century art – and it continued to be expanded until 1956. The MKK, meanwhile, was provisionally rehomed in Cappenberg Castle until its return to Dortmund in 1983.
In June 2009 the original building closed its doors, and the museum began relocating into the U-Tower, where it reopened under the new, shortened name Museum Ostwall in October 2010. The seven-storey tower, a former Dortmund Union brewery and warehouse, played a key role in the Ruhr Area's rebranding as "Culture Capital of Europe 2010" (RUHR.2010 – Kulturhauptstadt Europas). The museum reopened with the special exhibition "The Museum as Power Station" (Das Museum als Kraftwerk).