St Mark's Church is a former Anglican church in the Kemptown area of Brighton, part of the English city of Brighton and Hove. Originally intended as the private chapel of the adjacent St Mary's Hall school, it was partly built in 1838 at the request of Frederick Hervey, 1st Marquess of Bristol; but arguments over whether or not it should also be open to the public delayed its completion for more than 10 years. It became the parish church of Kemptown in 1873, but declining attendances resulted in a declaration of redundancy in 1986. At that time it was taken over by the school and became its chapel, nearly 150 years after this was first proposed.