Leszi or leshii (also leshy) are the male woodlands elves who protect wild animals in Slavic mythology. There could also be leshachikha/leszachka and leshonky - wife and children of Leszi.

A leszi has a close bond with the wolf, and often seen in the company of bears. He is said to shape-shift to any size, animal or plant. He is the Forest Lord and carries a club to express his rulership in the wood. In some tales he appears to visitors as a large talking mushroom. If one could be friends with the leszi, he would teach them the secrets of magic. He is considered akin to the devil in some areas. Farmers and sheep-herders would make pacts with the leszi to protect their crops and sheep.