Events from the year 1566 in Sweden

• Monarch – Eric XIV

• 26 March - 250 Swedes die in an attempt to capture Bohus Fortress.
• June - Nils Svantesson Sture falls from favor with the monarch and are exposed to public humiliation.
• 13 July – The Danes burn Bogesund.
• 15 July – The Danes burn Falköping.
• 23 July – The Danes burn Skara domkyrka.
• 26 July - Action of 26 July 1566
• - Ivan the Terrible ask to have the King's sister-in-law Catherine Jagiellon delivered as a hostage to use against Poland.
• - The Danes under Daniel Rantzau pillage Västergötland, while the Swedes pillage Skåne.

• 20 June - Sigismund III Vasa, monarch (died 1632)
• 15 October - Sigrid of Sweden (1566–1633), princess (died 1633)

• September 9 - Klas Horn, naval admiral (born 1517)
• Nils Svantesson Sture (c. 1543–1566): He was a prominent Swedish nobleman, part of the influential Sture family.