The Battle of Gembloux was fought between French and German forces in May 1940 during the Second World War. On 10 May 1940, The Nazi Wehrmacht, invaded Luxembourg, The Netherlands and Belgium under the operational plan Fall Gelb. Allied armies responded with the Dyle Plan, intended to halt the Germans in Belgium, believing it to be the main German thrust. The Allies committed their best and most mobile to an advance into Belgium on 10 May and on 12 May, the Germans began the second part of Fall Gelb, the Manstein Plan an advance through the Ardennes, to reach the English Channel and cut off the Allied forces in Belgium.

The Dyle Plan or Plan D was the plan of the Commander-in-Chief of the French Army, Général d'armée Maurice Gamelin, to defeat a German attempt to invade France through Belgium. The Dyle (Dijle) river is 86 km (53 mi) long, from Houtain-le-Val through Flemish Brabant and Antwerp; Gamelin intended French, British and Belgian troops to halt a German invasion force along the line of the river. The Franco-Belgian Accord of 1920 had co-ordinated communication and fortification efforts of both armies. After the German Remilitarization of the Rhineland on 7 March 1936, the Belgian government abrogated the accord and substituted a policy of strict neutrality, now that the German Army was on the German–Belgian border.