Major-General William Frederick Cavaye (15 February 1845 – 30 January 1926) was a British military officer and Municipal Reform Party politician.
He was the eldest son of General William Cavaye (d.1896) and his wife Isabella née Hutchinson, and was born in Edinburgh, Scotland. Following schooling at Edinburgh Academy and in Charlton he entered the Royal Military College, Sandhurst.
In 1865 Cavaye was commissioned as an ensign into the 107th Regiment of Foot. He rose through the officer ranks to become a lieutenant on 9 March 1867, a captain on 13 December 1874, and a major on 1 July 1881, having served with distinction in the Anglo-Zulu War of 1879. The 107th Foot became the 2nd Battalion of the Royal Sussex Regiment under the Childers reforms of 1881: Cavaye became the battalion's commanding officer with the rank of lieutenant-colonel on 15 August 1883.
Cavaye was further promoted, becoming Assistant Adjutant General and Chief of Staff of the Southern District with the rank of Colonel. He served ″on special service″ in the Second Boer War of 1899 – 1902, and was mentioned in dispatches. He was placed on half-pay on 24 March 1902.
Following the outbreak of the First World War, he returned to active service. He was appointed commanding officer of the 2nd East Anglian Division in November 1914 with the rank of brigadier-general. The division did not serve abroad, but Cavaye subsequently served on "special service" with the British Expeditionary Force in France from 1917 – 1919, and was raised to the rank of major-general. From 1919 – 1920 he was a King's Messenger.