Provinces of Japan (令制国, Ryōseikoku) were first-level administrative divisions of Japan from the 600s to 1868.

Provinces were established in Japan in the late 7th century under the Ritsuryō law system that formed the first central government. Each province was divided into districts (郡, gun) and grouped into one of the geographic regions or circuits known as the Gokishichidō (Five Home Provinces and Seven Circuits). Provincial borders often changed until the end of the Nara period (710 to 794), but remained unchanged from the Heian period (794 to 1185) until the Edo period (1603 to 1868). The provinces coexisted with the han (domain) system, the personal estates of feudal lords and warriors, and became secondary to the domains in the late Muromachi period (1336 to 1573).

The Provinces of Japan were replaced with the current prefecture system in the Fuhanken sanchisei during the Meiji Restoration from 1868 to 1871, except for Hokkaido, which was divided into provinces from 1869 to 1882. No order has ever been issued explicitly abolishing the provinces, but they are considered obsolete as administrative units. The provinces are still used in general conversation, especially in navigation and transportation, and referenced in products and geographical features of the prefectures covering their former territories.