31st Battalion
# 31st Battalion

31st Battalion may refer to:

* 31st Battalion, Royal Queensland Regiment, a unit of the Australian Army
* 31st/42nd Battalion, Royal Queensland Regiment, a unit of the Australian Army
* 2/31st Battalion (Australia), a unit of the Australian Army that was raised during World War II
* 31st (Alberta) Battalion, CEF, a unit of the Canadian Army
* 31st Infantry Battalion (Estonia), a unit of the Estonian Army
* 31st Engineer Battalion, a unit of the United States Army
* Combat Logistics Battalion 31, a unit of the United States Marine Corps
