The Symphony No. 9 in E minor was the last symphony written by the English composer Ralph Vaughan Williams. He composed it during 1956 and 1957, and it was given its premiere performance in London by the Royal Philharmonic Orchestra conducted by Sir Malcolm Sargent on 2 April 1958, in the composer's eighty-sixth year. The work was received respectfully but, at first, without great enthusiasm. Its reputation has subsequently grown, and the symphony has entered the repertoire, in the concert hall and on record, with the majority of recordings from the 1990s and the 21st century.

In his early sketches for the symphony, Vaughan Williams made explicit reference to characters and scenes in Thomas Hardy's Tess of the d'Urbervilles. By the time the symphony was complete he had deleted the programmatic details, but musical analysts have found many points in which the work nonetheless evokes the novel.