William Henley (1874–1957) was an English violinist, arranger of music, music teacher, and composer.

[1][a] He studied with August Wilhelmj and later became a professor of composition and principal of the violin at the Royal Academy of Music in London.

The seminal reference book the Universal Dictionary of Violin & Bow Makers is based on his notes.

The book was the first to include a significant number of American craftsmen.

Henley travelled extensively as a performer, primarily with his quartet.