The daimyo were the most powerful feudal rulers from the 12th century to the 19th century in the History of Japan. Similar to the feudal system in Europe, they held dynastic control over semi-autonomous territories, and lesser territorial lords were pledged to support greater ones. A warrior-caste of samurai soldiers likewise gave their personal loyalty to the support of lords from these families.

At the beginning of the Edo period, their clans and teritories were reorganized as han.

The term daimyo (大名) is also sometimes used to refer to the leading figures of such clans, also called "warlords". It was usually, though not exclusively, from these warlords that a shogun or regent was chosen.

See also: shogunate, History of Japan