Prince William Augustus Edward of Saxe-Weimar-Eisenach KP GCB GCH GCVO PC (11 October 1823 – 16 November 1902) was a British military officer of German parents. After a career in the Grenadier Guards, he became Major General commanding the Brigade of Guards and General Officer Commanding the Home District in 1870, General Officer Commanding Southern District in October 1878 and Commander-in-Chief, Ireland in October 1885. He was promoted to field marshal in 1897 despite his career including no great military achievements.

After being naturalised as a British subject, Edward's military career began on 1 June 1841, when, having trained at the Royal Military College, Sandhurst, he joined the 67th (South Hampshire) Regiment of Foot as an ensign. He was promoted to ensign in the Grenadier Guards and lieutenant in the Army on 8 June 1841 and lieutenant in his regiment and captain in the Army on 19 May 1846 before becoming adjutant of his battalion in November 1850.