Thomas Attwood Walmisley (21 January 1814 – 17 January 1856) was an English composer and organist.
He was born in London, the son of Thomas Forbes Gerrard Walmisley (1783-1856), a well-known organist and composer of church music and glees. Thomas Attwood was his godfather, and the boy was educated in music under their tuition.
Walmisley was organist of Croydon Parish Church in 1830 before becoming organist at Trinity College, Cambridge in 1833, and there he soon became prominent by his anthems and other compositions. He was simultaneously organist for the Choir of St John's College, Cambridge. He not only took the degrees of Mus.Bac. and Mus.Doc., but also graduated at Jesus College as BA and MA.
In 1836 Walmisley was made professor of music. His Cathedral Music was edited after his death by his father.
Walmisley is remembered chiefly for his Magnificat and Nunc dimittis in D minor, which have a place in the Anglican choral repertoire.
Walmisley died in 1856, and is buried in Brompton Cemetery.