The Polish 26th Infantry Division (Polish: 26 Dywizja Piechoty) was a unit of the Polish Army, which took part in the Polish September Campaign. It was formed as 4th Infantry Division (Poland) in southern Poland (former Austrian province of Galicia) in April 1919. Its regiments originally stationed in such towns as Cieszyn, Jarosław and Przemyśl.
In 1921, the Division was renamed into 26th I.D. and it was moved north - to Skierniewice and vicinity. It consisted of these regiments:
During the Invasion of Poland, the Division, under Colonel Adam Brzechwa-Ajdukiewicz, was part of Poznań Army, but on the fifth day of the war it was moved to Pomorze Army and, together with the 15th I.D., it created Operational Group of General Zdzisław Przyjałkowski.
On September 6, 1939, the Division was in the area of Inowrocław, soon afterwards it was used in the Battle of the Bzura, covering eastern wing of the Pomorze Army. After initial success of Polish offensive, during which the Division recaptured several locations, the Germans organized a counterattack. The 26th I.D. was subsequently destroyed.