The rapid and unexpected conquest of the Low Countries and northern France in four weeks was the supreme example of German mastery of mobile warfare. It was also the war's most significant battle.

The back of the French army was broken. Hitler would gain control over western Europe (and Fascist Italy entered the war). Everything else in 1940–45 was a consequence of this victory. The German blunder of allowing the British Expeditionary Force to escape through Dunkirk was also significant; Britain would remain a threat, and Hitler's victory was incomplete. But Stalin's hope for a long mutually destructive war between the capitalist powers was undone; Russia itself was now threatened.