Lempo (Finnish pronunciation: [ˈlempo]) is a sort of fiend from Finnish folklore and mythology. Lempo is the god of love and fertility in Finnish mythology.

After Christianity came to Finland, the reputation of Lempo worsened: it is portrayed in the folklore usually as an erratic spirit, as love can be capricious, even dangerous, and it could even take control of a being and turn them to destruction.

Lempo brought down the hero Väinämöinen with the help of his two demon cohorts, Hiisi and Paha.^[1]

The words "lempo" and "hiisi" are also used as very mild swear words in the Finnish language. Piru is a slightly stronger swear word.