Onathaar is a type of Theyyam performance during the Onam festival in Malabar region, especially in Kannur district in Kerala. During the ninth and tenth day (Uthradam and Thiruvonam) of Onam festival, small boys from Vannan community perform Onam Theyyam (Onathaar).

The dancer will carry a bell in his right hand and Onavillu, a bow-like musical instrument, in the left. The dancer will be accompanied by elder people from Vannan community along with Chenda. Onathaar will dance to the songs, which tell the legend of Mahabali (the legendary king who, according to myths, once ruled Kerala and in whose memory Keralites celebrate Onam every year).