The Battle of Gang Toi was fought on 8 November 1965 between Australian troops and the Viet Cong, during the Vietnam War. The battle was one of the first engagements between the two forces during the war and occurred when the 1st Battalion, Royal Australian Regiment struck a Viet Cong bunker system in the Gang Toi Hills, in northern Bien Hoa Province. The battle occurred during a major joint US- Australian operation codenamed Operation Hump, involving the US 173rd Airborne Brigade, to which 1RAR was attached.