Gerald Harman Walenn (19 November 1871 in London (England) – 29 January 1942 in Sydney (Australia)) was a British violinist and composer of classical music.
Gerald Walenn's father was a scientist and worked for many years at the Patent Office in London. His mother was musically trained, but did not studied music professionally. Nevertheless, her interest in music led to music professions of several of her children with Herbert Walenn being a violoncellist and professor at the Royal Academy of Music, Charles Walenn being a part of the J.C. Williamson Gilbert and Sullivan Opera Company, another brother became a prominent organist and Gerald Walenn together with a sister became violinists. Two other children found their way into art professions.
Gerald Walenn began playing the violin at the age of 8 under Kate Chaplin and later studied under John Rutson. He continued his violin studies at the Royal Academy of Music under the late Prosper Sainton and after his death under Emile Sauret.
He made his concert debut at the age of 14 with the Ballade for violin and orchestra op.16a by Moritz Moszkowski in the St James's Hall. He later performed at Osborne in the presence of Queen Victoria the Mendelssohn violin concerto. Gerald Walenn also made extensive concert tours throughout Great Britain and also the United States and Canada.
In 1903 he formed the Walenn String Quartet with Herbert Kinze (violin), James Lockyer (viola) his brother Herbert (cello). In later years the violist position was changed to Lionel Tertis. The quartet was disbanded in 1914 due to the beginning of World War I.