Thawun Gyi (Burmese: သဝန်ကြီး, pronounced [θəwʊ̀ɴ dʑí]; c. 1258 – 1317) was the founder and first ruler of Toungoo (Taungoo), the predecessor state of the Toungoo dynasty of Myanmar. The two-times-great-grandson of King Sithu II founded Toungoo near the end of the Pagan Empire in 1279. He became one of several independent rulers of petty states after the empire's breakup in 1287. He later submitted to Myinsaing, the new power in Upper Burma. Thawun Gyi was assassinated by the men of his younger brother Thawun Nge in 1317.