Symphony No. 66 (Haydn)

66 in B flat major (Hoboken I/66) is a symphony by Joseph Haydn.

The time of composition is uncertain, with one speculation from around 1775–1776.

[1] The symphony is scored for two oboes, two bassoons, two horns and strings.

[2] L.P. Burstein has noted Haydn's use of the VII♯ chord and the VII♯ → V progression in the first movement.

Brown has noted how Haydn reworked material from the symphony's first movement into other compositions, including an overture in D and two other symphonies.