Yiḏaki (Yirdaki) is a ceremonial instrument used by Yolŋu (Aboriginal People) in East Arnhemland, Australia. Yidaki are made from the termite-hollowed trunk of a tree (usually Stringybark, Eucalyptus Tetradonta) The trees are carefully selected and then finished to varying degrees. Yidaki are sometimes left plain, painted, or even wrapped in electrical tape. Beeswax mouthpiece are sometimes attached to help with creating a good seal for the lips.

Yidaki is primarily an instrument for Buŋgul (ceremony). During Buŋgul you will hear the Yiḏaki accompany the Bilma (clapsticks) and the Manikay (singing) and of course the Giritjirri (dancing). Buŋgul holds the law of the land and tells the stories and song-lines of the Yolŋu world. For the Yolŋu the Yiḏaki is not just a musical instrument but something that comes from the land, given by the creator ancestors.