The Battle of Crete (German Luftlandeschlacht um Kreta; Greek Μάχη της Κρήτης) was a battle during World War II on the Greek island of Crete. The battle began on the morning of 20 May 1941, when Nazi Germany launched an airborne invasion of Crete under the code-name Unternehmen Merkur (Operation MERCURY). Allied forces defended the island.

After one day of fighting, none of the objectives had been reached and the Germans had suffered appalling casualties. During the next day, through miscommunication and the failure of Allied commanders to grasp the situation, the Maleme airfield in western Crete fell to the Germans. The loss of Maleme enabled the Germans to fly in heavy reinforcements and overwhelm the Allied forces.

The battle of Crete was unique in three respects: it was the first mainly airborne invasion in history; it was the first time the Allies made significant use of the decipherment of the German Enigma code; and it was the first time invading German troops encountered mass resistance from a civilian population. The battle introduced a revolutionary form of warfare and may have had a significant impact on the course of events of the Second World War. In light of the heavy casualties suffered by the parachutists, Adolf Hitler forbade further airborne operations. Crete was dubbed "the graveyard of the German parachutists". However, the Allies were impressed by the potential of paratroopers and started to build their own airborne divisions.