He served in the Second Boer War in South Africa 1899–1900. During the early part of the war he commanded the Guards Brigade, including during the Battle of Modder River in November 1899. He took part in the Battle of Magersfontein on 10–11 December 1899, in which the defending Boer force defeated the advancing British forces amongst heavy casualties for the latter. Colvile was mentioned in the despatch from Lord Methuen describing the battle. The following year he was on 10 February 1900 appointed in command of the 9th Division, with the local rank of lieutenant-general whilst so employed. However, in May 1900, while Lord Roberts was closing in on Johannesburg, a Yeomanry battalion under Colvile's command was cut off and forced to surrender, Colvile was made a scapegoat and sent home. He retired 1901.