The Symphony No. 9 in D minor, Op. 125, also known as Beethoven's 9th, is the final complete symphony by Ludwig van Beethoven, composed between 1822 and 1824. It was first performed in Vienna on 7 May 1824. One of the best-known works in common practice music, it is regarded by many critics and musicologists as one of Beethoven's greatest works and one of the supreme achievements in the history of western music. In the 2010s, it stands as one of the most performed symphonies in the world.

The symphony was the first example of a major composer using voices in a symphony (thus making it a choral symphony). The words are sung during the final (4th) movement of the symphony by four vocal soloists and a chorus. They were taken from the "Ode to Joy", a poem written by Friedrich Schiller in 1785 and revised in 1803, with text additions made by Beethoven.