Lieutenant Colonel Harry Smith SG MC (born 25 July 1933) is a former senior officer in the Australian Army, seeing active service during the Malayan Emergency and the Vietnam War. He was Officer Commanding of D Company, 6th Battalion, Royal Australian Regiment (D Coy, 6RAR) during the Battle of Long Tan on 18 August 1966.After service as a Cadet and National Serviceman, Smith joined the Australian Regular Army as a private soldier and then graduated as Second Lieutenant from the Officer Cadet School, Portsea, in December 1952. He was subsequently posted to the 2nd Battalion, Royal Australian Regiment in 1955 and served during the Malayan Emergency between 1955 and 1957.From June 1966 to June 1967, Smith, then a major, was Officer Commanding D Coy, 6RAR. On 18 August, after heavy mortar shelling of the Australian base at Nui Dat the previous night, companies from 6RAR were sent out to locate the Vietcong units involved. Smith led the 105 soldiers of D Coy and the 3 man NZ Artillery Party out on patrol, but at 3.15pm, while patrolling a rubber plantation at Long Tan that afternoon, they encountered a reinforced regimental-sized Vietcong force (the Viet Cong 275th Regiment, supported by the North Vietnamese Army 806 Battalion and the local D445 Battalion) preparing to advance on the base.

Following service in Vietnam, Smith commanded 1 Commando Company at Georges Heights and after overseas training with UK, USA and Canadian airborne units, was posted as CO/CI of the first Army Parachute Training School in 1973. Smith left the Army in 1976 after a parachuting injury and later pursued cruising the east coast and gulf, covering 150,000 nautical miles over 33 years .In 2008, after years of campaigning for better recognition of Long Tan veterans, Smith's MC was upgraded to the Star of Gallantry (the Australian replacement for the Imperial DSO). Two of his officers who fought at Long Tan had their MID awards upgraded to Medals for Gallantry corresponding to the original nom.