15th Brigade or 15th Infantry Brigade may refer to:

• 15th Brigade (Australia)

• 15th Brigade (Brazil)

• 15th Infantry Brigade (Greece)

• 15th Infantry Brigade (Hungary)

• 15th (Imperial Service) Cavalry Brigade

• 15th Brigade (Japan)

• 15th Mechanized Brigade (Romania)

• 15th Separate Guards Motor Rifle Brigade

• XV International Brigade

• 15th Infantry Brigade (United Kingdom)
• 15th Mounted Brigade (United Kingdom)
• Artillery Brigades
  • 15th Brigade Royal Field Artillery
  • XV Brigade, Royal Horse Artillery

• 15th Sustainment Brigade (United States)

• XV Corps (disambiguation)
• 15th Army (disambiguation)
• 15th Division (disambiguation)
• 15th Group (disambiguation)
• 15th Wing (disambiguation)
• 15th Regiment (disambiguation)
• 15 Squadron (disambiguation)