The Toccata and Fugue in D minor, BWV 565, is a composition for organ by, according to the oldest sources, German composer Johann Sebastian Bachand is one of the most widely recognisable works in the organ repertoire. Although the date of its origin is unknown, scholars have suggested between 1704 and the 1750s. The piece opens with a toccata section followed by a fugue that ends in a coda, and is largely typical of the north German organ school of the Baroque era.

Little was known about its early existence until the piece was discovered in an undated manuscript produced by Johannes Ringk. It was first published in 1833 during the early Bach Revival period through the efforts of composer Felix Mendelssohn, who also performed the piece in 1840. It was not until the 20th century that its popularity rose above that of other organ compositions by Bach, as exemplified by its inclusion in Walt Disney's 1940 animated film Fantasia that featured Leopold Stokowski's orchestral transcription from 1927.

The piece has been subject to a wide, and often conflicting, variety of analyses. It is often described as a type of program music depicting a storm, while its depiction in Fantasia is suggestive of non-representational or absolute music. Scholars such as Peter Williams and Rolf Dietrich Claus argued against its authenticity, while Christoph Wolff defended the attribution to Bach. Other commentators ignored the doubts over its authenticity, or considered the attribution issue undecided.