Field Marshal Sir John Lyon Chapple, GCB, CBE (born 27th May 1931) was a career British Army officer in the second half of the 20th century. He served as Chief of the General Staff, the professional head of the British Army, from 1988 to 1992. Early in his early military career he saw action during the Malayan Emergency and again during the Indonesia–Malaysia confrontation and later in his career he provided advice to the British Government during the Gulf War.
Born the son of C H Chapple and educated at Haileybury College, Chapple undertook National Service and was commissioned as a second lieutenant in the Royal Artillery on 3 June 1950. He went to Trinity College, Cambridge in October 1951 and, while still at University, was transferred to the King's Regiment as a second lieutenant on 4 December 1952, and to the South Lancashire Regiment also in the same rank on 20 October 1953. He became a lieutenant in the South Lancashire Regiment on 27 May 1954 and, on leaving University, was transferred to the 2nd King Edward VII's Own Gurkha Rifles (The Sirmoor Rifles) on 3 August 1954 retaining his rank as a lieutenant.
Chapple served with the regiment in Malaya, Hong Kong and Borneo and was promoted to captain on 9 February 1957 and to major on 9 February 1964. Appointed MBE in the Queen's Birthday Honours 1969 and promoted to lieutenant-colonel on 31 December 1969, he was appointed Commanding Officer of 1 Battalion 2nd Gurkha Rifles in 1970 and a member of the Directing Staff at the Staff College, Camberley in 1972. After spending much of the year as a services fellow at Fitzwilliam College, Cambridge in 1973, he was posted to the Directorate of Staff Duties at the Ministry of Defence at the end of the year and, having been promoted to colonel on 31 December 1973 and to brigadier on 31 December 1975, was made Commander of 48 Gurkha Infantry Brigade in 1976. He became Principal Staff Officer to the Chief of the Defence Staff in 1978, and having been appointed CBE in the Queen's Birthday Honours 1980, he became Commander of British Forces in Hong Kong on 13 June 1980, with the substantive rank of major-general from 1 January 1981. He returned to the UK to be Director of Military Operations at the Ministry of Defence on 19 October 1982.
Appointed KCB in the Queen's Birthday Honours 1985, he became Deputy Chief of the Defence Staff (Programmes and Personnel) on 2 January 1985 in the rank of lieutenant-general and was then appointed Commander-in-Chief, UK Land Forces on 1 June 1987 with the rank of general from 29 June 1987. He was appointed ADC to the Queen on 6 October 1987 and advanced to GCB in the Queen's Birthday Honours 1988. His last appointment was as Chief of the General Staff from 10 September 1988. He served in this post, in which he provided military advice to the British Government on the conduct of the Gulf War, until he retired with promotion to field marshal on 13 February 1992.
He was appointed Colonel of the 2nd King Edward VII's Own Gurka Rifles (The Sirmoor Rifles) on 14 September 1986 and Honorary Colonel of the Oxford University Officers Training Corps on 21 July 1987.
He was also a trustee of the Gurkha Museum from 1973 to 2003, a trustee of the National Army Museum from 1981 to 2003, a trustee of the World Wildlife Fund UK from 1988 to 1993, President of the Zoological Society of London from 1992 to 1994 and Governor of Gibraltar from 1993 to 1995.