| 31st Battalion, Royal Queensland Regiment | |
|---|---|
 Cap badge of the Royal Queensland Regiment | |
| Active | 1881–2008 |
| Country |  Queensland Australia |
| Allegiance | Queensland Australia |
| Branch | Queensland Defence Force Australian Army Reserve |
| Type | Infantry |
| Role | Line infantry (formerly) Light infantry |
| Size | Battalion |
| Part of | 11th Brigade, 2nd Division |
| Garrison/HQ | Jezzine Barracks, Townsville, Queensland |
| Nickname(s) | Kennedy Regiment |
| Colours | Chocolate and gold |
| March | John Peel |
| Engagements | World War I |
| Insignia | |
| Unit colour patch |  |
The 31st Battalion, Royal Queensland Regiment (31 RQR) was a Reserve infantry battalion of the Australian Army. Although it was officially formed as 31 RQR in 1965 the battalion can trace its lineage back to units formed in 1881 as part of the colonial defence forces of the state of Queensland.
Over the course of the unit's 127-year history, the unit has largely been used for home service, although it was awarded 42 battle honours. During the Second Boer War members from the battalion went to South Africa as part of the Queensland contingent, for which the battalion received its first battle honour. In 1914, the battalion was the first Australian infantry unit mobilised for service during World War I when it was sent to garrison Thursday Island after fears of possible German military action in the Pacific. Later many members of the battalion enlisted in the Australian Imperial Force (AIF), serving on the Western Front in France and Belgium. During World War II, the battalion was amalgamated with the 51st Battalion, Far North Queensland Regiment, initially serving as garrison troops in Dutch New Guinea before taking an active part in the fighting against the Japanese in the Bougainville campaign in 1944–45.
After the war the battalion underwent a number of changes in organisation and designation before 1965 when it was redesignated as the 31st Battalion, Royal Queensland Regiment. Since then the battalion has formed part of the 11th Brigade. In 1976, due to manpower shortages, the battalion was reduced to an independent rifle company before being re-raised as a full battalion again in 1986. In January 2008, the battalion was amalgamated with the 42nd Battalion, Royal Queensland Regiment (42 RQR) to form the 31st/42nd Battalion, Royal Queensland Regiment (31/42 RQR).