Francis Llewellyn Harrison, better known as "Frank Harrison" or "Frank Ll. Harrison" (29 September 1905 – 29 December 1987) was one of the leading musicologists of his time and a pioneering ethnomusicologist. Initially trained as an organist and composer, he turned to musicology in the early 1950s, first specialising in English and Irish music of the Middle Ages and increasingly turning to ethnomusicological subjects in the course of his career. His Music in Medieval Britain (1958) is still a standard work on the subject, and Time, Place and Music (1973) is a key textbook on ethnomusicology.