The Battle of Fromelles, sometimes known as the Action at Fromelles or the Battle of Fleurbaix, occurred in France on July 19-20, 1916, during World War I. The action was intended partly as a diversion to Battle of the Somme, that was taking place about 80 kilometres (50 mi) to the south and an operation to retake a salient just north of the German-occupied village of Fromelles, 16 kilometres (9.9 mi) from the city of Lille,
Fromelles was a combined operation between British troops and the Australian Imperial Force (AIF). It would be the first occasion that the AIF saw action on the Western Front.
After a night and a day of fighting, 1,500 British and 5,533 Australian soldiers were killed, wounded or taken prisoner. The Australian War Memorial describes the battle as "the worst 24 hours in Australia's entire history."
It was a decisive victory for Germany, and the Australian and British losses were sustained without the Allies gaining any ground.