Seii (c. 1326 – 1349) was the second king of the Okinawan kingdom of Chūzan. He succeeded his father, Tamagusuku, in 1336, at the age of ten. His reign is characterized by the meddling of his mother in government affairs, and her corruption. The king's mother took advantage of her privileges and position, and severely damaged popular support for her son.
Seii died in 1349. The Governor of Urasoe, Satto, seized power for himself.