The 'Battle of Tomaszów Lubelski' was fought between German and Polish forces near the town of Tomaszów Lubelski in Poland (17/26 September 1939).

The battle was the second largest engagement after the 'Battle of the Bzura' in the Germans 'Weiss' (i) invasion of Poland battle and also the largest armoured battle of the campaign. It resulted in the surrender of the Armia 'Krakow' on 20 September 1939. The battle can be divided into two phases, the first taking place on 10/20 September and the second on 21/26 September.

In the first phase the Polish forces, comprising Generał brygady Tadeusz Piskor’s Armia 'Lublin' and Generał dywizji Antoni Szylling’s Armia 'Krakow' attempted to break through the German positions around Tomaszów towards the Romanian 'bridgehead' area. On 15 September, both of these armies were in the area to the south-west of Frampol. Their movement to the south was blocked, however, by the presence two German formations, namely General Ernst Busch’s VIII Corps round Biłgoraj, and General Ewald von Kleist’s XXII Corps (mot.), comprising Generalleutnant Rudolf Veiel’s 2^nd Panzerdivision and Generalleutnant Dr Alfred Ritter von Hubicki’s 4^th leichte Division, round Hrubieszów, Zamość and Tomaszów Lubelski. The Polish forces, concentrated around Frampol, were thus surrounded by six to seven German divisions. Since neither the Armia 'Kraków' nor the Armia 'Lublin' had any aircraft, Szylling decided to risk an attack on the Germans without knowing their real strength. He knew that Panzer forces had already approached Rawa Ruska, and hoped that their units would be stretched comparatively thinly along the road linking Jarosław and Rawa. The Polish forces included one of the largest Polish armoured units of that time, the Warsaw Armoured Motorised Brigade, and Szyling and Piskor decided that this brigade would make a demonstration attack on Tomaszów, drawing the attention of the Germans.

The combined Polish forces were the 3^rd, 21^st, 22^nd, 23^rd and 55^th Divisions, as well as the 1^st Mountain Brigade, the Kraków Cavalry Brigade and the Warsaw Armoured Motorised Brigade. However, after days of heavy fighting, the Polish formations and units other than the armoured brigade had been reduced to something between 30% and 50% of their original strength, and lacked artillery, anti-tank ammunition and other equipment. On the other side of the tactical coin, however, communication between the various divisions was good, and they had a good idea about the movements and locations of the German forces.

The Polish plans were quickly changed, however, after the Germans destroyed a key Polish formation, the 21^st Mountain Division, near the village of Dzikowiec, on 15/16 September, in the process killing its commander, Generał brygady Józef Kustroń. Realising that German forces were stronger than he had thought, Piskor decided to act quickly and without waiting for all his divisions to complete their concentration. On 17 September Piskor ordered Warsaw Armoured Motorised Brigade to attack Tomaszów and keep the town until the main strength of the Armia 'Kraków' arrived to join it. The attack on Tomaszów took place in the morning of 18 September, and by 13.00 half of the town was in Polish hands. Meanwhile, however, the 4^th leichte Division had entered the fray, striking rear Polish units and forcing their withdrawal. Thus, the attempt to capture Tomaszów in a surprise attack failed. During the night of 18/19 September the Warsaw Brigade, supported by infantry of 23^rd and 55^th Divisions, attacked Tomaszów again, but without success. A third attack took place during the night of 19/20 September, but the Polish units were disorganised and demoralised. After a series of chaotic skirmishes, with number of killed and wounded growing, and supplies of ammunition shrinking, Piskor decided to surrender. Some 11,000 Polish men were taken prisoner, though small groups managed to hide in forests.

Meanwhile, Generał brygady Mieczysław Boruta-Spiechowicz’s Operational Group 'Boruta', which was part of the Armia 'Kraków', separated from the Polish main forces and marched toward Narol. Surrounded by the Germans, the Polish formations and units were destroyed individually. Some Polish men managed to reach the area of Rawa Ruska, where 3,000 soldiers surrendered on 20 September, ending this first phase of the battle.

The second phase of the battle involved Polish formations and units of the so-called Northern Front, which comprised the remaining elements of the Armia 'Lublin', Armia 'Modlin', Operational Groups 'Wyszków' and 'Narew' and the Nowogródzka Cavalry Brigade under Generałs brygady Emil Krukowicz-Przedrzymirski and Stefan Dąb-Biernacki. On 20 September these forces were some 25 miles (40 km) to the north of Tomaszów in the area of Sitaniec. Dąb-Biernacki, who commanded them, until the final hours had no idea about the ongoing battle and therefore did not help the fighting troops. At the same time, Piskor knew nothing about Dąb-Biernacki’s units operating to the north-east of Tomaszów. Altogether, the Northern Front had 39,000 men and 225 pieces of artillery. They were divided into three groups: the cavalry of Generał brygady Władysław Anders, the operational group of Generał brygady Jan Kruszewski, and the operational group of Generał brygady Emil Krukowicz-Przedrzymirski. The Polish forces were in no way a match for the German forces of General Walter von Reichenau’s 10^th Army and General Wilhelm List’s 14^th Army, which were holding the roads to the south, but at a meeting of his officers on 18 September in the village of Wereszcze Duże near Chełm, Dąb-Biernacki decided to go along with an attempt to break through to Hungary or Romania. Dąb-Biernacki already knew that the USSR had invaded eastern Poland on the previous day, so time was of crucial importance.

The Northern Front’s forces marched to the south from the area of Chełm in two columns toward Zamość, which Dąb-Biernacki decided to attack. On 18 September the Poles attacked Krasnystaw, but failed to capture it. On next day, Dąb-Biernacki ordered the attack on Zamość to be carried out on 20 September, but on the night of 19/20 September he learned of the ongoing 'Battle of Tomaszów Lubelski' and decided to help. Northern Front units headed toward Tomaszów, but in the evening of 20 September, these came under attack by the 4^th leichte Division and Generalleutnant Friedrich Bergmann’s 27^th Division near Cześniki. Meanwhile, units of Krukowicz-Przedrzymirski’s operational group had reached the area of Tomaszów, and on 21 September, a few hours after the first phase of the battle had ended, attacked troops under command of Busch (Generalleutnant Hans von Obstfelder’s 28^th Division and Generalmajor Gustav Höhne’s 8^th Division). Since the Polish forces proved to be stronger than expected, List decided to reinforce Busch in the form of Generalleutnant Georg Braun’s 68^th Division, the 27^th Division and the 2^nd Panzerdivision, which had just mopped up the Polish forces in the first phase of the 'Battle of Tomaszów Lubelski'.

During the evening of 22 Septemberm Anders’s cavalry attacked, capturing Krasnystaw and then reaching Sambor. Other Polish units were not successful, and in several skirmishes were surrounded on 23 September. Dąb-Biernacki ordered his officers to capitulate, while he himself escaped the encirclement and left Poland eventually to reach France. Przedrzymirski refused to obey the order, and on 24 September attacked Krasnobród, but was then stopped by the 8^th Division. Most of the remaining Polish forces capitulated on or around 26 September.