Roy Galbraith Henderson CBE (4 July 1899 – 16 March 2000) was a British baritone singer, conductor and teacher.

Born in Edinburgh and raised in Nottingham, Henderson began singing in public during the First World War, entertaining his army colleagues. After the war he enrolled at the Royal Academy of Music (RAM) in London, where he won numerous prizes. Professionally he came to public notice in 1925 deputising at short notice in the difficult and important baritone part in Frederick Delius's A Mass of Life at a London concert. He maintained a successful concert career for the next 27 years, taking part in the premieres of many works by British composers.

Henderson appeared in opera in two seasons at Covent Garden in 1928 and 1929, and was a founding member of the company of the Glyndebourne Festival, singing there in every season from 1935 to 1939. He was also well known as a recitalist, performing classic and new songs. He made many recordings, mainly for the Decca company, although he is particularly remembered for HMV's recordings from Glyndebourne and a 1938 Columbia recording of Ralph Vaughan Williams's Serenade to Music in which Henderson and fifteen other leading British singers took part. In addition to singing he was a conductor, mostly of choral music, and made some recordings in that capacity.

From the start of his career Henderson aimed to be a teacher of singing. He took pupils from the late 1920s onwards, and was a professor at the RAM from 1940. In 1953 he retired from public performance and devoted himself to full-time teaching. Among his many pupils the best-known was Kathleen Ferrier, and others included Jennifer Vyvyan (soprano), Constance Shacklock (mezzo-soprano), Norma Procter (contralto), Thomas Round (tenor) and John Shirley-Quirk and Derek Hammond-Stroud (baritones).