St. Eustachius Church, Tavistock is a Grade II listed parish church, located in Tavistock, Devon.
A church was established on this site as early as 1193 but certainly by 1265. Abbot Robert Champeaux of Tavistock Abbey rebuilt it in 1318 with further building work carried out in 1352 and 1380. It was largely rebuilt in the 15th century when a new chancel was added at the east end. The south aisle was added between 1445 and 1447 as a bequest from Constance Coffyn.
Between 1844 and 1845, major restoration was carried out by the architect John Hayward. The gallery was removed and a new organ bay in the north aisle was added, along with vestries south of the chancel. In 1896, the font was moved to the west end of the south aisle.
More restoration work was undertaken between 1902 and 1903 by the architect George Fellowes Prynne. The choir stalls were removed from the chancel and new marble flooring was installed. The nave and aisles were re-floored and the rooves were overhauled, also with new figures of angels restored to the positions occupied previously by similar figures. New brass lighting pendants were suspended from the roof and the seating was re-spaced.
It is unknown when the first organ was installed, but it is recorded that it needed repairs in 1538. By the 1790s there was a barrel organ in a gallery. In 1802 this was replaced, then again in 1825. The current organ was built by J.W. Walker and Sons and was opened by Samuel Sebastian Wesley on 25 June 1846. The carved statues on the organ case were added in 1879. There were later modifications and additions by Hele and Company of Plymouth and Lance Foy which has resulted in a three manual organ with 51 stops. A specification of the organ can be found in the National Pipe Organ Register.