Brigadier General Walter Long, CMG, DSO (26 July 1879 – 27 January 1917) was a British soldier.
The eldest son of the 1st Viscount Long and his wife Lady Dorothy (Doreen) Boyle, he was baptized 11 September 1879 at St John's Church, West Ashton, Trowbridge, Wiltshire.
Educated at Harrow, he joined the Royal Scots Greys in May 1899. In November of that year he went with his regiment to South Africa to serve in the Second Boer War, where he took part in the ride under Sir John French to the relief of Kimberley, Northern Cape, and was badly wounded at Dronfield. On return to duty he was appointed ADC to General Sir Bruce Hamilton. He served throughout the campaign, and was promoted to Captain on 23 April 1902. He was mentioned in dispatches several times in South Africa (including the Final Despatch by Lord Kitchener dated 23 June 1902), and while there, gained the Distinguished Service Order (DSO), the Queen's South Africa Medal and the King's South Africa Medal, each with two clasps. When he returned to England, he was made ADC to Sir Harry Scobell commanding the First Cavalry Brigade at Aldershot. Long resigned this appointment in order to return to his regiment. After serving with his regiment for some years, he went to India as additional ADC to General Sir Garrett O'Moore Creagh, and afterwards he went to Canada to serve as ADC to the Duke of Connaught.