The 15th (Imperial Service) Cavalry Brigade was a brigade-sized formation that served alongside British Empire forces in the Sinai and Palestine Campaign, during the First World War. Originally called the Imperial Service Cavalry Brigade it was formed from Imperial Service Troops provided by the Indian Princely States of Hyderabad, Mysore, Patiala and Jodhpur, which each provided a regiment of lancers. A maximum of three regiments served in the brigade at any one time. The states of Bhavnagar, Kashmir, Kathiawar and Idar provided smaller detachments for the brigade, which was at times reinforced by other British Empire regiments and artillery batteries when on operations.