Lieutenant General Sir Leonard Whitmore Thornton, KCB, CBE (15 October 1916 – 10 June 1999) was a senior officer in the New Zealand Army.

Born in Christchurch, Thornton joined the Royal New Zealand Artillery in 1937 after having been encouraged by his uncle, Leonard Isitt, to pursue a military career.

After holding a series of senior posts in the New Zealand Army, including a period as its commander, he was appointed Chief of the Defence Staff in 1965 for a six-year term.

His uncle, Leonard Isitt, was at the time the commander of the RNZAF air base in Hobsonville and he encouraged Thornton to also join the military.

Thornton embarked with the first echelon on 6 January 1940[10] which arrived in Egypt at Maadi Camp, the main 2NZEF base in the Middle East, on 11 February.

[11] He led 25 Battery during the Battle of Greece, which helped cover the Allied retreats at Platamon and Tempe before it was evacuated to the island of Crete.

Although he returned to command of the 5th Field Regiment after the dissolution of the New Zealand Corps, Freyberg brought him back to the divisional staff as its senior operations officer.

[5] After the war, Thornton performed occupation duties with Jayforce, in Japan, where he was the Senior British Liaison Officer in the Tokyo sub-area.

He was dispatched to England in 1952 to attend the Imperial Defence College after which he led the New Zealand Joint Services Liaison Staff in London.

During this time, in which New Zealand's military affairs were dominated by the country's involvement in the Korean War, Thornton began to demonstrate the diplomatic skills that would prove useful during his later career.

This was to prove a challenging term for Thornton for, driven by the Labour Government, there was a significant change in New Zealand defence policy.

While not a policy Thornton personally agreed with, he oversaw the reorganisation that was required to achieve the desired structure and this saw some longstanding regiments being amalgamated.

Thornton was the second Chief of Defence Staff, succeeding Vice Admiral Sir Peter Phipps, and went on to complete a six-year term in this capacity, after which he retired from the army in the rank of lieutenant general in October 1971.