15th Brigade or 15th Infantry Brigade may refer to:
Australia 15th Brigade (Australia)
Brazil 15th Brigade (Brazil)
Greece 15th Infantry Brigade (Greece)
Hungary 15th Infantry Brigade (Hungary)
India 15th (Imperial Service) Cavalry Brigade 15th Indian Infantry Brigade
Indonesia 15th Infantry Brigade (Indonesia)
Japan 15th Brigade (Japan)
New Zealand 15th Brigade (New Zealand)
Romania 15th Mechanized Brigade
Russia 15th Separate Guards Motor Rifle Brigade
Slovenia 15th Aviation Brigade (Slovenian Armed Forces)
Soviet Union 15th Independent Special Forces Brigade
Spain XV International Brigade
Ukraine 15th Artillery Reconnaissance Brigade 15th Operational Brigade 15th Transport Aviation Brigade
United Kingdom 15th Anti-Aircraft Brigade 15th Infantry Brigade (United Kingdom) 15th Mounted Brigade 15th Reserve Brigade Artillery units 15th Brigade Royal Field Artillery XV Brigade, Royal Horse Artillery
United States 15th Military Police Brigade 15th Signal Brigade 15th Sustainment Brigade
See also XV Corps (disambiguation) 15th Army (disambiguation) 15th Division (disambiguation) 15th Group (disambiguation) 15th Wing (disambiguation) 15th Regiment (disambiguation) 15 Squadron (disambiguation)