Kalmar Bloodbath (Swedish: Kalmar blodbad) in Kalmar, Sweden, on 16 May 1599 was the public execution by beheading of 22 people: three Swedish nobles and a priest, the governors Johan Sparre, Kristoffer Andersson (Gyllengrip), Lars Andersson Rålamb and the chaplain Birger, and the execution by hanging of the secretaries, custodians and mercenary officers.
The executions took place in the aftermath of the Battle of Stångebro (September 1598) and the de facto deposition of the Polish and Swedish King Sigismund III Vasa as King of Sweden by his uncle, the Swedish regent Duke Charles. After the Battle of Stångebro, the forces of Duke Charles laid siege to Kalmar, which was controlled by the loyalists of Sigismund. The city fell after a month, and after a further month, Kalmar Castle was taken on 12 May. The victory was followed by the execution of 22 people as Sigismund loyalists without trial. The heads of the governors were placed on poles above the Western city gate.