Caen (UK: /ˈkɒ̃ ˈkɒn/; French: [kɑ̃] ^ⓘ; Norman: Kaem) is a city and commune 15 km (9.3 mi) inland from the northwestern coast of France. It is the prefecture of the department of Calvados. The city proper has 105,512 inhabitants (as of 2018^[update]), while its functional urban area has 470,000, making Caen the second largest urban area in Normandy and the 19th largest in France. It is also the third largest commune in all of Normandy after Le Havre and Rouen.

Caen is located 200 km (120 mi) northwest of Paris, connected to the South of England by the Caen (Ouistreham) to Portsmouth ferry route through the English Channel. Situated a few miles from the coast, the landing beaches, the bustling resorts of Deauville and Cabourg, as well as Norman Switzerland and the Pays d'Auge, Caen is often considered the archetype of Normandy.

Caen is known for its historical buildings built during the reign of William the Conqueror, who was buried there, and for the Battle for Caen, heavy fighting that took place in and around Caen during the Battle of Normandy in 1944, destroying much of the city. The city has now preserved the memory by erecting a memorial and a museum dedicated to peace, the Mémorial de Caen.

The first references to the name of Caen are found in different acts of the dukes of Normandy: Cadon 1021/1025, Cadumus 1025, Cathim 1026/1027. Year 1070 of the Parker manuscript of the Anglo-Saxon Chronicle refers to Caen as Kadum, and year 1086 of the Laud manuscript gives the name as Caþum. Despite a lack of sources as to the origin of the settlements, the name Caen would seem to be of Gaulish origin, from the words catu-, referring to military activities and magos, field, hence meaning "manoeuvre field" or "battlefield". In Layamon's Brut, the poet asserts that King Arthur named the city in memory of Sir Kay, although the historicity of King Arthur is widely doubted.

Caen was known in Roman times as 'Catumagos', from the Gaulish roots magos meaning 'field' and catu meaning 'combat'. It remained a minor settlement throughout the Roman period and began to see major development commence in the 10th century, under the patronage of the Dukes of Normandy. Around 1060, William the Conqueror began construction of the Château de Caen, which became the centre of the ducal court. Duchess Matilda of Flanders also founded the Benedictine Abbey of Sainte-Trinité, Caen around the same time, eventually being buried in the abbey. Caen succeeded Bayeux as the capital of Lower Normandy, complementing the second ducal capital of Rouen.

Caen fell to Philip II of France on 21 May 1204, and was incorporated along with the remainder of Normandy into the Kingdom of France.

In 1346, King Edward III of England led his army against the city, hoping to loot it. It was expected that a siege of perhaps several weeks would be required, but the army took the city in less than a day, on 26 July 1346, storming and sacking it, killing 3,000 of its citizens, and burning much of the merchants' quarter on the Île St-Jean. Only the castle of Caen held out, despite attempts to besiege it. A few days later, the English left, marching to the east and on to their victory at the Battle of Crécy. It was later captured following a siege by Henry V in 1417 and treated harshly for being the first town to put up any resistance to his invasion. In 1450 towards the end of the war, French forces recaptured Caen.

During World War II, Caen was captured by German forces during the Battle of France in 1940 and placed under military occupation. In 1944, Allied forces launched Operation Overlord, invading German-occupied France and rapidly advancing through Normandy. From 6 June to 6 August 1944, the British Second Army fought the battle of Caen to dislodge German forces from the city. During the battle, Allied bombing raids heavily damaged the city and caused numerous French civilian casualties. After the battle, little of prewar Caen remained, and reconstruction efforts in the city continued until 1962.