John (Giovanni Battista) Barbirolli (December 2, 1899 - July 29, 1970), was a British conductor and cellist.

A Londoner, from a musical family, his father and uncle being violinists in London theatre orchestras, notably the Leicester Square Empire, though they had also played at la Scala, Milan, under Toscanini. Thus the young John was destined to be a string player, a specialist in British Music, and to have a love of Italian Opera.

As a young cellist he made some acoustic records, played in the London Symphony Orchestra (LSO), notably at the first performance of Elgar's Cello Concerto, and was soon after the soloist in the second performance of the work. In the 1920s he turned to conducting and formed a chamber orchestra which recorded new works for the National Gramophone Society, notably Elgar's Introduction and Allegro, which may have been responsible for HMV avoiding the work until after Elgar's death.

Barbirolli became known for his ability to secure effective performances at short notice, and in the 1930's made many recordings with the LSO and London Philharmonic, accompanying concertos with leading soloists such as Kreisler, Heifetz and Rubinstein, most of which remain classics today.

In 1937 Barbirolli achieved a coup when he was invited to succeed Toscanini as conductor of the New York Philharmonic, a tremendously prestigious post. Although his five seasons there were a musical triumph, as surviving recordings show, he was under constant attack from the trenchant New York press, notably the anglophobe critic Olin Downes.

In 1942 Barbirolli was invited to renew his contract but to do so would have to become a US citizen, which he was unwilling to do. At this point an invitation to take up the chief conductorship of the Hallé Orchestra in Manchester transformed his career.

The increase in scope for concerts had prompted the Hallé to end the increasingly unsatisfactory arrangement of sharing half their players with the BBC, which had saved them in the slump years, and to engage a top-rank conductor. Only four of the shared players chose to join the Hallé, so when Barbirolli arrived he had to rebuild the orchestra in weeks, a task he fell to with enthusiasm. His "new Hallé" can be heard today in recordings of symphonies by Bax and Vaughan Williams, made in wartime Manchester.

Barbirolli conducted the orchestra for twenty-five years, in many cities including the Cheltenham Festival, where he premiered many new works. He also conducted the BBC and other London orchestras in concert and on records, and towards the end of his life renewed his association with EMI which produced a legacy of fine recorded performances, many of which have been available continuously.

Barbirolli is remembered as an interpreter of Elgar, Vaughan Williams and Mahler, but also of Schubert, Beethoven, Verdi and Puccini, and as a staunch supporter of new works by British composers, in which his advocacy rivalled that of Boult and Henry Wood.