Australia

• 3rd Army Tank Brigade (Australia)
• 3rd Brigade (Australia)
• 3rd Light Horse Brigade
  3rd Light Horse Brigade
  The 3rd Light Horse Brigade was a mounted infantry brigade of the First Australian Imperial Force which served in the Middle Eastern theatre of World War I....
  
  

Poland

• 3rd Brigade of the Polish Legions
• 3rd Polish Infantry Brigade
  3rd Polish Infantry Brigade
  The 3rd Polish Infantry Brigade was a Polish infantry brigade which served during World War II. Together with the 10th Armoured Cavalry Brigade they formed part of the 1st Polish Armoured Division and was created from Polish soldiers who had already escaped from Poland to France, and after the...
  
  
• Polish 3rd Mountain Brigade
  Polish 3rd Mountain Brigade
  3rd Mountain Brigade was a unit of the Polish Army, which took part in the Polish September Campaign in 1939. Commanded by Colonel Jan Stefan Kotowicz, it was part of Operational Group “Slovakia” of Armia Karpaty...
  
  

United Kingdom

• 3 Commando Brigade
  3 Commando Brigade
  3 Commando Brigade is a commando formation of the British Armed Forces and the main manoeuvre formation of the Royal Marines. Its personnel are predominantly Royal Marines, supported by units of Royal Engineers, Royal Artillery, The Rifles, and the Fleet Air Arm, together with other Commando...
  
  
• 3rd Infantry Brigade (United Kingdom)
• 3rd Parachute Brigade (United Kingdom)

United States

• 3rd Brigade, 1st Infantry Division (United States)
• 3rd Brigade, 1st Cavalry Division (United States)
• 3rd Brigade, 7th Infantry Division (United States)
  3rd Brigade, 7th Infantry Division (United States)
  The 3rd Brigade, 7th Infantry Division, originally known as the 14th Infantry Brigade was an infantry brigade of the United States Army, and a part of the 7th Infantry Division. The brigade was based at Fort Ord, California for most of its history....
  
  
• 3rd Brigade Combat Team, 10th Mountain Division (United States)
  3rd Brigade Combat Team, 10th Mountain Division (United States)
  The 3rd Brigade Combat Team, 10th Mountain Division is an infantry Brigade Combat Team of the United States Army based at Fort Drum, New York...
  
  
• 3rd Brigade, 24th Infantry Division (United States)
  3rd Brigade, 24th Infantry Division (United States)
  The 3rd Brigade, 24th Infantry Division was an infantry brigade of the United States Army. Before its most recent deactivation in 2006, it was based at Fort Benning, Georgia...
  
  
• 3rd Brigade, 104th Division (United States)
  3rd Brigade, 104th Division (United States)
  The 3rd Brigade, 104th Division is an infantry brigade of the United States Army. It is a training component of the United States Army Reserve, and subordinate to the 104th Division based in Fort Lewis, Washington...
  
  
• 3rd Marine Expeditionary Brigade (United States)
  3rd Marine Expeditionary Brigade (United States)
  The 3rd Marine Expeditionary Brigade is a United States Marine Corps unit that is the "middleweight" crises response force of choice in the Pacific Area of Operation...
  
  
• 3rd Signal Brigade (United States)
  3rd Signal Brigade (United States)
  The 3d Signal Brigade of the United States Army was an element of III Corps. It was based at Fort Hood, Texas, but was inactivated on 15 April 2008 as part of the transformation of the U.S. Army to a Modular Force Structure...
  
  
• 3rd Sustainment Brigade (United States)
  3rd Sustainment Brigade (United States)
  The 3rd Sustainment Brigade is a sustainment brigade of the United States Army headquartered at Fort Stewart, Georgia. The 3rd Sustainment Brigade is responsible for providing logistical support to the 3rd Infantry Division, however the modular nature of the brigade means that it takes on other...