In Finnish mythology, Ukko (Estonian spelling Uku) is a god of sky, weather, crops (harvest) and other natural things. He is also the most significant god in Finnish mythology and the Finnish word ukkonen, thunderstorm, is derived from his name. In the Kalevala he is also called ylijumala (the high god), as he is the god of things above. He makes all his appearances in myths solely by natural effects when asked. "Ukko" in contemporary Finnish means "old man". He is the equivalent of Odin in the Norse pantheon, with properties of Thor. The equivalent of Thor, Tuuri, was seldom encountered in the Finnish pantheon, and relegated only as deity of harvest and success.
Ukko was sometimes known as the same god as Perkele and as Ilmarinen, the blacksmith of Kalevala. His wife was Rauni the protecter of rowan tree, known as the Mother-Earth or Akka. Finns believed that when it stormed, Ukko and Akka were making love.