Bel canto (Italian for 'beautiful singing' / 'beautiful song', Italian: [ˈbɛl ˈkanto])—with several similar constructions (belcanto, bellezze del canto, bell'arte del canto, pronounced in American English as /bɛl ˈkɑːntoʊ/ ^ⓘ)—is a term with several meanings that relate to Italian singing, and whose definitions have often been misunderstood. Bel canto was not only seen as a vocal technique, but also as a source of national pride for Italians, specifically in how the musical qualities aligned with their identity. However, this pride was often complicated by political circumstances.

The phrase was not associated with a school of singing until the middle of the 19th century, when writers in the early 1860s used it nostalgically to describe a manner of singing that had begun to wane around 1830. Nonetheless, "neither musical nor general dictionaries saw fit to attempt [a] definition [of bel canto] until after 1900". The term remains vague and ambiguous in the 21st century and is often used to evoke a lost singing tradition.

As generally understood today, the term bel canto refers to the Italian-originated vocal style that prevailed throughout most of Europe during the 18th and early 19th centuries. Late 19th- and 20th-century sources "would lead us to believe that bel canto was restricted to beauty and evenness of tone, legato phrasing, and skill in executing highly florid passages, but contemporary documents [those of the late 18th and early 19th centuries] describe a multifaceted manner of performance far beyond these confines". The main features of the bel canto style were:

The Harvard Dictionary of Music by Willi Apel says that bel canto denotes "the Italian vocal technique of the 18th century, with its emphasis on beauty of sound and brilliance of performance rather than dramatic expression or romantic emotion. In spite of the repeated reactions against bel canto (or its abuses, such as display for its own sake; Gluck, Wagner) and the frequent exaggeration of its virtuoso element (coloratura), it must be considered as a highly artistic technique and the only proper one for Italian opera and for Mozart. Its early development is closely bound up with that of the Italian opera seria (A. Scarlatti, N. Porpora, J. A. Hasse, N. Jommelli, N. Piccinni)."

Since the bel canto style flourished in the 18th and early 19th centuries, the music of Handel and his contemporaries, as well as that of Mozart and Rossini, benefits from an application of bel canto principles. Operas received the most dramatic use of the techniques, but the bel canto style applies equally to oratorio, though in a somewhat less flamboyant way. The da capo arias these works contained provided challenges for singers, as the repeat of the opening section prevented the story line from progressing. Nonetheless, singers needed to keep the emotional drama moving forward, and so they used the principles of bel canto to help them render the repeated material in a new emotional guise. They also incorporated embellishments of all sorts (Domenico Corri said da capo arias were invented for that purpose [The Singer's Preceptor, vol. 1, p. 3]), but not every singer was equipped to do this, some writers, notably Domenico Corri himself, suggesting that singing without ornamentation was an acceptable practice (see The Singer's Preceptor, vol. 1, p. 3). Singers regularly embellished both arias and recitatives, but did so by tailoring their embellishments to the prevailing sentiments of the piece.

Two famous 18th-century teachers of the style were Antonio Bernacchi (1685–1756) and Nicola Porpora (1686–1768), but many others existed. A number of these teachers were castrati. Singer/author John Potter declares in his book Tenor: History of a Voice that:

For much of the 18th century castrati defined the art of singing; it was the loss of their irrecoverable skills that in time created the myth of bel canto, a way of singing and conceptualizing singing that was entirely different from anything that the world had heard before or would hear again.

In another application, the term bel canto is sometimes attached to Italian operas written by Vincenzo Bellini (1801–1835) and Gaetano Donizetti (1797–1848). These composers wrote bravura works for the stage during what musicologists sometimes call the "bel canto era". But the style of singing had started to change around 1830, Michael Balfe writing of the new method of teaching that was required for the music of Bellini and Donizetti (A New Universal Method of Singing, 1857, p. iii), and so the operas of Bellini and Donizetti actually were the vehicles for a new era of singing. The last important opera role for a castrato was written in 1824 by Giacomo Meyerbeer (1791–1864).