31st Brigade or 31st Infantry Brigade may refer to: 31st Brigade (Australia) 31st Brigade (France) 31st Mechanized Infantry Brigade (Greece) 31st Indian Brigade of the British Indian Army in the First World War 31st Indian Infantry Brigade of the British Indian Army in the Second World War 31st Mechanized Brigade (Soviet Union) 31st Air Defense Artillery Brigade (United States) United Kingdom 31st (North Midland) Anti-Aircraft Brigade 31st Brigade (United Kingdom) See also 31st Division (disambiguation) 31st Group (disambiguation) 31st Regiment (disambiguation) 31st Battalion (disambiguation) 31st Squadron (disambiguation)