William Havergal Brian (29 January 1876 – 28 November 1972) was a prominent 20th-century English composer, librettist, and church organist.

He is best known for having composed 32 symphonies, an unusually high number amongst his contemporaries, 25 of them after the age of 70. His best-known work is his Symphony No. 1, The Gothic, which calls for some of the largest orchestral forces demanded by a conventionally structured concert work.

He also composed five operas and a number of other orchestral works, as well as songs, choral music and a small amount of chamber music. Brian enjoyed a period of popularity earlier in his career and rediscovery in the 1950s, but public performances of his music have remained rare and he has been described as a cult composer. He continued to be extremely productive late into his career, composing large works even into his nineties, most of which remained unperformed during his lifetime.