31st Brigade

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 Mechanized Brigade (Ukraine)
 * 31st Air Defense Artillery Brigade (United States)
 * 31st (North Midland) Anti-Aircraft Brigade (United Kingdom)
 * 31st Brigade (United Kingdom)