The battle of Fehrmarn (Swedish: Sjöslaget vid Femern; Danish: Slaget ved Rødsand; Dutch: Zeeslag bij Fehmarn) occurred on 30 April, 1659 during the Dano-Swedish War of 1658–1660.

On 30 April, 1659, a Swedish fleet under the command of Klas Hansson Bjelkenstjerna encountered its Dutch counterpart under Jacob van Wassenaer Obdam and the Danish one under a certain Bielke between Fehrmarn and Lolland.

During the fighting, a six pound cannonball hit Bjelkenstjerna in his hip, forcing him to withdraw to the stern, leading to Carl Gustaf Wrangel taking over command.

[4] The Swedish losses sustained during the battle were some 12 officers and men killed, with 26 wounded, and the size of the allied fleet remains unknown.

[4] According to some sources, the battle ended in a draw[4][5][7][8] while others claim it was tactically inconclusive but with a strategic outcome favoring the allies.