The Handel and Haydn Society is an American chorus and period instrument orchestra based in Boston, Massachusetts. Known colloquially as 'H+H', the organization has been in continual performance since its founding in 1815, the longest serving such performing arts organization in the United States.

The Handel and Haydn Society was founded as an oratorio society in Boston on March 24, 1815, by a group of Boston merchants and musicians, "to promote the love of good music and a better performance of it". The founders, Gottlieb Graupner, Thomas Smith Webb, Amasa Winchester, and Matthew S. Parker, described their aims as "cultivating and improving a correct taste in the performance of Sacred Music, and also to introduce into more general practice, the works of Handel, Haydn, and other eminent composers." The society made its debut on Christmas Day, December 25, 1815, at King's Chapel (then Stone Chapel), with a chorus of 90 men and 10 women. The early chorus members were middle-class tradesmen drawn from the choirs of local churches. Only men could be members, while a far smaller number of women were invited to participate. In its early decades the society hired what musicians it could afford and used unpaid amateurs to complete the orchestra or sometimes substituted organ for orchestra.

Jonas Chickering, at the start of his career as a piano manufacturer, joined the society in 1818 at age 20 and later became its president. The society was also an early promoter of composer Lowell Mason, publishing his first collection of hymns in 1822 and later electing him as the group's president. Profits from the sales of that hymnbook and a second collection of sacred music subsidized the society for several decades.

The Handel and Haydn Society has given a number of notable American premieres, including Handel's Messiah in 1818, and Haydn's The Creation in 1819. The society also sponsored the first American publication of an edition of Messiah in 1816. It presented the U.S. premieres of musical settings by many baroque and classical composers, including Mozart and Bach. An 1818 assessment in the New England Palladium magazine said:

We know there is a fashion in admiration, but the exertions of these gentlemen have continuously presented us with something more and more worthy to be admired. It is doubtless to them that we must ascribe in great measure the improved taste in Sacred Music that is prevailing among us.

Some early reviews noted that public interest waned after a few years as many standard works were repeated. John Rowe Parker wrote in the Euterpeiad:

There have been many instances where a deficiency of patronage has been manifested ... and it cannot be too evident that this deficiency, was more owing to the deficiencies in genius and in practice, than in any unwillingness on the part of the public, to award the meed of excellence.

The society's principal chronicler believes that repeating repertoire was necessary to support "much rehearsing until the inexperienced singers could master that which special enthusiasm had carried through in rough outline." Membership from the start and well into the 20th century was limited to men, though the chorus, which was first dominated by male voices, was soon roughly balanced between male and female.