| Conflict: | Siege of Copenhagen |
| Place: | Copenhagen, Denmark |
| Date: | 4 April – 16 June 1368 |
| Coordinates: | 55.6761°N 12.5683°W |
| Territory: | Copenhagen occupied by the Hanseatic League |
| Result: | Hanseatic victory |
| Combatant1: | Hanseatic League |
| Commander1: | Unknown |
| Commander2: | Unknown |
| Strength1: | 37 ships 2,000 men |
| Strength2: | Unknown |
| Casualties1: | Unknown |
| Casualties2: | Unknown |
| Units1: | Unknown |
| Units2: | Absalon's Castle garrison |
| Partof: | the Danish-Hanseatic War (1361–1370) |
The Siege of Copenhagen or the Capture of Copenhagen, was a looting and siege of Copenhagen and Absalon's Castle in 1368 between Denmark and the Hanseatic League, during the Danish-Hanseatic War (1361–1370). The city was looted and Absalon's castle was destroyed.
In November 1367, members of the Hanseatic diet held in Cologne formed a confederation to defeat the Valdemar IV of Denmark. The confederation received support from Count Adolf of Holstein and Albert, King of Sweden. The war began when King Albert invaded Scania, quickly taking cities like Falsterbo, Ystad, and Simrishamn. Meanwhile, Nicholas, Count of Holstein-Rendsburg invaded Jutland taking Ribe and Viborg.
With 37 ships and 2,000 armed men, the main fleet weighted anchor from Lübeck on 4 April 1368, with Copenhagen as their target. Includingly, 400 horses, 8 trebuchets, 4 catapults, and several battering rams were also on board. When the fleet reached Copenhagen, the city quickly fell, however, Absalon's castle still held out. The castle would continue to do this for the next couple of weeks until the garrison surrendered with permission to move away freely.
The Hanseatic leader describes the looting of the fort as follows:It seems that the king's property was not allowed to be taken away by the Danes. Now an important choice was to be made, and after much consideration, the Hanseatics agreed to destroy Absalon's Castle. As such they could hinder the Danes in retaking Copenhagen.