Byng was deployed in November 1899 to South Africa, where he was to act as a provost marshal, but was instead immediately given the local rank of lieutenant colonel and tasked with raising and commanding the South African Light Horse during the Second Boer War. Byng thereafter served on the front lines, during which time he ended up in command of a group of columns, was mentioned in despatches five times (including by Lord Kitchener on 23 June 1902), and in November 1900 was promoted to brevet lieutenant colonel and in February 1902 to brevet colonel. The beginning of 1902 brought more significant events for Byng, with his return to England in March, an audience with King Edward VII the following month, at which he was appointed to the Royal Victorian Order as a member 4th class (MVO), and his marriage to Evelyn Moreton at St Paul's Church, Knightsbridge, on 30 April 1902. Following a second visit to the King in early October, Byng was sent back to India to command the 10th Royal Hussars at Mhow and was appointed to the rank of a substantive lieutenant colonel on 11 October 1902.