John Baptiste Calkin (16 March 1827, London – 15 April 1905, Hornsey, London) was an English composer, organist and music teacher.
Calkin got his musical education from his father James Calkin (1786–1862), a pianist, cellist and composer. From 1846 to 1853, he worked as an organist, preceptor and choirmaster at the St. Columba's College in Dublin. After his return to London, he was organist at several churches and also a professor at the Guildhall School of Music and Drama and later at the Croydon Conservatory.
His most known work is the setting from 1872 of a popular Christmas song I Heard the Bells on Christmas Day by Henry Wadsworth Longfellow. He also composed church music, hymns and anthems.