Sithu of Pinya (Burmese: စည်သူ, [sìθù]; also known as Myinsaing Sithu) was regent of Pinya from 1340 to 1344. He is not mentioned in any of the royal chronicles. He only appears in a Pinya era inscription as "King" Myinsaing Sithu. Sithu, who according to the inscription succeeded Uzana I, may have been a caretaker for his nephew and son-in-law Kyawswa I of Pinya.