| Conflict: | Action of 4 June 1565 |
| Partof: | Northern Seven Years' War |
| Date: | 4 June 1565 |
| Place: | Bay of Mecklenburg |
| Result: | Swedish victory |
| Combatant1: |  Sweden |
| Combatant2: | Denmark–Norway Lübeck |
| Commander1: | Klas Horn |
| Commander2: | Herluf Trolle |
| Strength1: | 49 ships (including merchant ships) |
| Strength2: | 33 ships |
| Casualties1: | Unknown |
| Casualties2: | 700 men |
| Units1: | Sankt Erik Finska Svan Svenska Hektor Herkules Engel Pelikan Troilus Fuchs |
| Units2: | Jegermesther Merkurius Svenske Jomfru |
This battle took place on 4 June 1565 between an allied fleet of 33 Danish and Lübecker ships, under Trolle, and a Swedish fleet of around 49 ships, under Klas Horn. Afterward, the Danes retired to Køge Bay, south of Copenhagen, where Trolle died of his wounds on 25 June. His second, Jørgen Brahe, died of fever on 28 June.