Geoffrey Winzer Gilbert (28 May 1914 – 1989) was an English flautist, who was a leading influence on British flute-playing, introducing a more flexible style, based on French techniques, with metal instruments replacing the traditional wood. He was a prominent member of five British symphony orchestras between 1930 and 1961, and in 1948 he founded a chamber ensemble of leading wind players.
After the Second World War Gilbert combined his playing career with teaching, holding appointments at music colleges in London, Manchester, and finally in Florida.
Gilbert was born in Liverpool, England, the son of Ernest Gilbert, an oboist, and his wife Jessie, née Thomas, a teacher. At the age of fourteen he won a scholarship to the Royal Manchester College of Music (RMCM), and joined the Hallé and the Liverpool Philharmonic orchestras two years later. In 1933 Gilbert joined Sir Thomas Beecham's London Philharmonic Orchestra; he was its principal flautist at the age of nineteen.
At the time, British players still used the traditional wooden flute, which was blown strongly and with no vibrato. Gilbert recognised that French players such as Marcel Moyse, who played on metal flutes, could produce a far wider range of tone-colour. In 1937 he took lessons from the French flautist René le Roy (and also from the violinist Carl Flesch). With le Roy's encouragement he bought a Louis Lot silver flute, altered his embouchure and articulation, and mastered the use of vibrato to play in what the Grove Dictionary of Music and Musicians calls "the flexible and expressive French style". According to The Times, "his subsequent influence on other British flautists was enormous, and the wooden flute was quickly superseded".
Gilbert remained with the LPO until the outbreak of the Second World War in 1939, when he volunteered to join the Coldstream Guards. He remained nominally the orchestra's principal flautist until 1942, and managed to play in some concerts. He rejoined the London Philharmonic after the war (though Beecham was no longer its conductor), and became a teacher at the Guildhall School of Music and Trinity College of Music, London. His students included William Bennett, James Galway, Susan Milan, Stephen Preston and Trevor Wye.