Sir Alfred Herbert Brewer (21 June 1865 – 1 March 1928) was an English composer and organist. As organist of Gloucester Cathedral from 1896 until his death, he contributed a good deal to the Three Choirs Festival for 30 years.

Brewer lived in Gloucester his whole life. He was the organist at two of its churches, and also founded the city's choral society in 1905. He had been a Gloucester Cathedral chorister in his boyhood, and began his organ studies there under C. H. Lloyd. He was educated at the Cathedral School, Oxford and at the Royal College of Music.

In 1913, at the Three Choirs Festival in Gloucester, Brewer was entrusted with conducting the premiere of Sibelius's tone-poem for soprano and orchestra, Luonnotar, Op. 70. The soloist was Aino Ackté.

As a composer, Brewer was fairly conservative. His output includes church music of all types, cantatas, songs, instrumental works, and orchestral music. The greater part of his life was devoted to the advancement of the standards of ecclesiastical music. Some of it has been recorded on the Priory label. His Magnificat and Nunc dimittis in D major are in the standard repertoire of Anglican church music. He was knighted in 1926.