Kokutai (国体, "national body/structure of state") is a concept in the Japanese language translatable as "system of government", "sovereignty", "national identity, essence and character", "national polity; body politic; national entity; basis for the Emperor's sovereignty; Japanese constitution". The word is also a short form of the (unrelated) name for the National Sports Festival of Japan.

The nationalistic essence of kokutai is thought of as the uniqueness of the Japanese polity as issuing from a leader of divine origin.