Yun Bayin (Burmese: ယွန်းဘုရင်, pronounced [jʊ́ɴ bəjɪ̀ɴ]; lit. King of the Yun) (1558–1564) is one of the 37 nats in the official pantheon of Burmese nats. He was King Mekuti Sutthiwong (Thai: เมกุฏิสุทธิวงศ์) or Mae Ku (Thai: แมกุ), the captive king of Lanna Kingdom, who died of illness during the reign of King Bayinnaung of Toungoo (1551–1581). He is portrayed sitting with right knee raised, right hand holding a sheathed sword across the shoulder, and left hand on left knee.
Bayinnaung captured Chiang Mai during the Burmese-Siam War of 1563. Mae Ku then became a tributary king.