Aiatar may refer to:
In Estonian and Finnish mythology, the Aiatar was a female demon that manifested frequently in the form of a dragon or serpent. She lived in forests and lonely sections of the Tundra and spread pestilence and disease. She is also known as "the devil of the woods". The Aiatar is a local variation of the Aitvaras of Lithuania and the Ai of other parts of Estonia. "Ajatar" may be derived from the Finnish verb ajattaa "to make one pursue".