Kii (紀伊国; -no kuni) or Kishu (紀州 kishū) was a province of Japan in the part of Honshu that is today Wakayama and the southern part of Mie Prefecture. Kii bordered Ise, Izumi, Kawachi, Shima, and Yamato Provinces. The Kii Peninsula takes its name from this province.

During the Edo period, the Kii branch of the Tokugawa clan had its castle at Wakayama.