The Blue Danube is the common English title of An der schönen blauen Donau, Op. 314 (German for "By the Beautiful Blue Danube"), a waltz by the Austrian composer Johann Strauss II, composed in 1866.

The piece was prominently used in the Stanley Kubrick film 2001: A Space Odyssey. The waltz is heard as a space plane approaches and docks with a space station, and then again while another spacecraft travels from the station to the Moon. It is also heard over the film's closing credits.