1742 in music

• March 23 – Johann Sebastian Bach revives his St Matthew Passion BWV 244 (BC D 3b) with some further revisions of instrumentation and voicing at St. Thomas Church, Leipzig: the work is now scored with a ripieno soprano choir and viola da gamba and harpsichord in the second orchestra (the organ for this orchestra is under repair).
• April 13 – First performance of Handel's oratorio Messiah staged at the Music Hall in Fishamble Street, Dublin[1] in aid of local charities. Matthew Dubourg leads the orchestra. Handel leaves Ireland on 13 August.
• December 7 – The Berlin Court Opera is inaugurated with a performance of Carl Heinrich Graun's Cleopatra e Cesare.
• Joseph Benda joins the Prussian royal orchestra.

• Carl Philipp Emanuel Bach – 6 Harpsichord Sonatas, Wq.48 (Nuremberg: Balthasar Schmid) (composed 1740–1742)
• Francesco Barsanti – A Collection of Old Scots Tunes(Edinburgh: Alexander Baillie)
• Jean-Joseph Mouret – Motets à une et deux voix avec symphonie (Paris: la Veuve Mouret, Mme Boivin, Le Sr Le Clerc)
• Jacques-Christophe Naudot – 6 Concertos en quatre parties, for hurdy-gurdy, musette, flute, recorder, or oboe, with two violins and continuo, Op. 17 (Paris)
• John Parry – Antient British music, or A collection of tunes, never before published, which are retained by the Cambro-Britons... part 1, containing 24 airs... (London: Mickleborough), compiled with Evan Williams, contains the first appearance of the melody now used for "Deck the Halls"

• Carl Philipp Emanuel Bach
  • Harpsichord Concerto in G major, H.412, Wq. 9
  • 6 Harpsichord Sonatas, Wq.49 (published 1744)
• Johann Sebastian Bach
  • Mer hahn en neue Oberkeet, BWV 212 ("Peasant Cantata")
  • The Art of Fugue (Die Kunst der Fuge), BWV 1080, earliest known manuscript (P200)
• Louis-Nicolas Clérambault – Motets, Book I (Books I–V were all composed and published between 1742–1760 but no exact dates survive)
• Michel Corrette – Concerto Turc (No. 19 from Concertos Comiques)
• Christoph Graupner
  • Trio Sonata in G minor, GWV 215
  • Concerto for 2 Chalumeaux in C major, GWV 303
• George Frideric Handel – Messiah (first performed, composed 1741)
• Johann Adolph Hasse – I pellegrini al sepolcro di Nostro Signore (oratorio)
• Giovanni Battista Martini – 12 Sonate d’intavolatura per l’organo e ’l cembalo (published 1747 in Bologna)
• Johann Melchio Molter
  • Clarinet Concerto in D major, MWV 6.36
  • Clarinet Concerto in D major, MWV 6.38
• Jacques-Christophe Naudot – Suite en trio, Op. 18
• Giovanni Benedetto Platti – 6 Harpsichord Sonatas 'sur le goût italien' (published in Nuremberg, 1742)
• Franz Xaver Richter – Kemptener Te Deum
• Giovanni Battista Sammartini – 12 Sonatas, Op. 2
• Domenico Scarlatti – Keyboard sonatas K. 31–93 presented to the queen.

• Giuseppe Carcani – Demetrio
• Baldassare Galuppi – Scipione in Cartagine
• Carl Heinrich Graun – Cesare e Cleopatra
• Johann Adolph Hasse
  • La Didone abbandonata
  • Lucio Papirio
• Niccolò Jommelli – Don Chichibio
• Leonardo Leo – Andromaca
• Gennaro Manna – Tito Manlio

Francesco Valls – Mapa Armónico Práctico

• January 15 – Simon Leduc (died 1777)
• May 8 – Jean-Baptiste Krumpholz, Czech composer (died 1790)
• July 19 – Jean-Baptiste Davaux (died 1822)
• August 19 – Jean Dauberval, French dancer (died 1806)
• Probable date – Martha Ray, English singer (murdered 1779)

• January 24 (buried) – Benedikt Anton Aufschnaiter, Austrian composer (born 1665)
• April 16 – Stefano Benedetto Pallavicino, Paduan-born librettist (born 1672)
• June 28 – Jan Josef Ignác Brentner, Czech composer (born 1689)
• July 22 – Andrea Adami da Bolsena, Italian castrato, master of the papal choir (born 1663)
• July 12 – Evaristo Felice Dall'Abaco, Veronese-born violinist and composer (born 1675)
• August 25 – Carlos Seixas, Portuguese composer (born 1704)
• date unknown
  • Matteo Goffriller, Italian cello-maker (born 1659)
  • Giovanni Mossi (born c. 1680)