William Primrose CBE was a Scottish violist and teacher.
Primrose was born in Glasgow and studied violin initially. In 1919 he moved to study at the then Guildhall School of Music in London. From there he moved to Belgium to study under Eugène Ysaÿe who encouraged him to take up the viola instead. In 1930, he joined Warwick Evans, John Pennington, and Thomas Petre as the violist in the London String Quartet. The group dissolved in 1935. In 1937, he began playing in the NBC Symphony Orchestra under Arturo Toscanini. When it was rumored that Toscanini would leave the Symphony in 1941, Primrose resigned. His career as a soloist took off when he started touring with Richard Crooks. He later signed with Arthur Judson, an influential concert manager. In 1946, he was the soloist in the first recording of Berlioz's Harold in Italy.
In 1944 he had commissioned a viola concerto from Béla Bartók. This was left incomplete at Bartók's death in 1945, and had to wait four years for its completion by Tibor Serly. Primrose was the soloist in the world premiere performance of the concerto, on 2 December 1949.
In 1950 Benjamin Britten wrote for him Lachrymae based on the song by Dowland.