Polish 3rd Legions Infantry Division (3. Dywizja Piechoty Legionów) was a tactical unit of the Polish Army between the World Wars. Formed in 1919, as a third unit composed significantly of veterans of the Polish Legions in World War I (after Polish 1st Legions Infantry Division and Polish 2nd Legions Infantry Division), the unit saw extensive action during the Polish-Bolshevik War and World War II. In the interbellum period, it was stationed in Zamość.
During the Polish-Bolshevik War it was commanded by Edward Śmigły-Rydz (and others). It took part in the battle of Daugavpils, Kiev Offensive, battle of Warsaw (1920) and battle of Niemen.
During the Polish Defensive War it was a part of Army Prusy under command of col. Marian Turkowski. After a week of fighting, it was forced back and dispersed by German XV Motorised Corps. Parts of the division were lated reorganized under 1st Legions Divisions and continued to fight until late September.
There were at least four other 3rd Infantry Divisions in Polish twentieth century military history. There was a 3rd Infantry Division which attained partially formed status with the Polish Army in France (1939–1940), there was the 3rd Carpathian Rifle Division served with II Corps (Poland), Polish Armed Forces in the West, the 3rd Infantry Division of the Home Army, and another 3rd Infantry Division (pl:3 Pomorska Dywizja Piechoty) served with the First Army, Soviet-controlled Polish Armed Forces in the East. This division fought at the Battle of Kolberg (1945). In 1962 it became the 3rd Mechanised Division.