"A Fifth of Beethoven" is a disco instrumental recorded by Walter Murphy and the Big Apple Band, adapted from the first movement of Ludwig van Beethoven's Symphony No. 5. The record was produced by production music and sound effects recording producer Thomas J. Valentino. The "Fifth" in the song's title is a pun, referencing a liquid measure approximately equal to one-fifth of a gallon, a popular size for bottles containing liquor, as well as Beethoven's Fifth Symphony from which the song was adapted.

The Symphony No. 5 in C minor, Op. 67, also known as the Fate Symphony, is a symphony composed by Ludwig van Beethoven between 1804 and 1808. It is one of the best-known compositions in classical music and one of the most frequently played symphonies, and it is widely considered one of the cornerstones of western music. First performed in Vienna's Theater an der Wien in 1808, the work achieved its prodigious reputation soon afterward. E. T. A. Hoffmann described the symphony as "one of the most important works of the time". As is typical of symphonies during the Classical period, Beethoven's Fifth Symphony has four movements.