Sir Felix Maximilian Schoenbrunn Cassel, 1st Baronet, PC, QC, JP (16 September 1869 – 22 February 1953) was a German-born British barrister and politician who served as Judge Advocate-General, the senior civilian lawyer of the War Office (and later also the Air Ministry) responsible for the administration of courts-martial, from 1915 to 1934. He was called to the Bar at Lincoln's Inn in 1894 and took silk in 1906, practising in Chancery. He became a bencher of Lincoln's Inn in 1912 and treasurer in 1935.