The Symphony No. 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. The symphony is scored for two oboes, two bassoons, two horns and strings.

Date of composition 1776 (1775-1776)
Type Symphony
Tonality B-flat Major
Catalogue Hob. I:66
Approx. duration 30 minutes
Spoken language German
Instruments Orchestra
Autotranslations beta Joseph Haydn: Symphonie n°66 en si bémol majeur, Hob. I:66
Franz Joseph Haydn: Sinfonia n. 66 in si bemolle maggiore, Hob. I:66
Joseph Haydn: Sinfonie Nr. 66 B-dur, Hob. I:66