Knut Jönsson Posse (Finnish: Nuutti Posse; died 25 March 1500) was a Swedish general in Sweden and Finland remembered for the Vyborg Bang (1495) and for his surprise attack on the Danish Army at the Battle of Brunkeberg (1471).

In 1471, Regent Sten Sture ordered Posse to load the garrison of Stockholm Castle onto boats to ready a surprise attack on the Danish and German Army of King Christian I of Denmark.

Soon after the battle started, Christian I sent more troops to reinforce their position near Sankta Klara kloster.

[2] From 1495 to 1497, Posse was governor of Vyborg Castle, and commanded the garrison during the 1495 siege by forces of the Grand Duchy of Moscow.

He successfully defeated the much larger Russian army by luring the attackers onto the walls and detonating an explosive mine under their feet, in what became known as 'the Vyborg Bang' (Swedish: Viborgska Smällen, Finnish: Viipurin pamaus).