Major Guy Temple Montacute Larnach-Nevill, 4th Marquess of Abergavenny, JP, DL (15 July 1883 – 30 March 1954)[1] was a British peer.

Guy was born at Saxonbury Lodge, Frant, Sussex,[2] the eldest son of Lord George Montacute Nevill and his wife Florence Mary Soanes.

[3] He married Isabel Nellie Larnach (d. 5 November 1953), the only child of James Walker Larnach, on 30 October 1909,[3] and had three children: After the death of his father-in-law, he changed his surname (for himself and his wife only) from Nevill to Larnach-Nevill by deed poll on 17 June 1919.

Larnach-Nevill succeeded to the marquessate in 1938 on the death of his uncle, Henry Nevill, 3rd Marquess of Abergavenny, who died after a fall from his horse, with no surviving male issue.

[3] His daughter Lady Angela Isabel married Digby Pepys, 7th Earl of Cottenham.