In February 1847, he joined his battalion at the Cape. The first Kaffir War had just broken out, and Buller was at once appointed to the command of a brigade, and eventually of the 2nd Division. In September 1847 he was appointed second in command to Sir George Berkeley in the campaign in the Amatola mountains, in which his battalion chased Sandilli so hotly that the chief surrendered to Buller on 19 October. He was gazetted Companion of the Order of the Bath in December 1847. In 1848 he served under Sir Harry Smith in the War against Pretorius, and on 29 August led the attack on the Boomplaats, where he was severely wounded, and had his horse killed under him. His battalion now came home, but in 1852 he was again ordered to go with his regiment to the Cape. At the head of a brigade in General Somerset's division he burnt the kraals in the Waterkloof in the Second Kaffir War, and was present at the Battle of Berea, where he was publicly thanked by Sir George Cathcart, and eventually succeeded Somerset in the command of his division in August 1852.