123rd

123rd may refer to:

Germany

 * 123rd Infantry Division (German Empire)
 * 123rd Infantry Division (Wehrmacht)

India

 * 123rd Indian Infantry Brigade
 * 123rd Outram's Rifles, an infantry regiment of the British Indian Army

Japan

 * 123rd Division (Imperial Japanese Army)

Poland

 * Polish 123rd Fighter Escadrille, one of the fighter units of the Polish Army in 1939

Soviet Union

 * 123rd Guards Motor Rifle Division

United Kingdom

 * 123rd Battalion (Royal Grenadiers), CEF, a unit in the Canadian Expeditionary Force during the First World War
 * 123rd Brigade
 * 123rd Light Anti-Aircraft Regiment, Royal Artillery
 * 123rd Regiment of Foot (1762), an infantry regiment of the British Army, formed in 1762 and disbanded in 1764
 * 123rd Regiment of Foot (Loyal Lincolnshire), an infantry regiment of the British Army, formed in 1794 and disbanded in 1796

United States

 * 123d Airlift Wing
 * 123rd Field Artillery Regiment
 * [[123d Fighter Squadron]
 * 123rd Infantry Regiment (United States)
 * 123rd Contingency Response Group, a unit of the 123rd Airlift Wing, Kentucky Air National Guard
 * 123rd Illinois Volunteer Infantry Regiment, an infantry regiment that served in the Union Army during the American Civil War
 * 123rd Indiana Infantry Regiment
 * [[123rd New York Volunteer Infantry]
 * 123rd Ohio Infantry
 * 123rd Pennsylvania Infantry