Ezo

is a Japanese name which historically referred to the lands to the north of Japan. It was used in various different senses, sometimes meaning the northern Japanese island of Hokkaidō, and sometimes meaning lands and waters further north in the Sea of Okhotsk. The word Ezo could also refer to the peoples that the Japanese encountered in these lands.

The spelling Ezo reflects the pronunciation in Modern Standard Japanese. The spelling Yezo reflects its pronunciation circa 1600 AD, when Europeans first came in contact with Japan. It is this historical spelling that is reflected in the scientific Latin term yezoensis, as in Fragaria yezoensis and Porphyra yezoensis.

Ezo can refer to:

* The major northern Japanese island of Hokkaidō (until 1869).
* The short-lived Republic of Ezo on Hokkaidō.
* The lands around the Sea of Okhotsk (historical usage).
* The Ainu people, and more vaguely, any peoples with whom the Japanese came into contact to their north.
* The Red Ezo, a name historically used by the Japanese for the Russians of the Far East, normally Siberian Cossacks, on account of their supposedly red hair. Once the Japanese had clearly identified these people as Russians (in Japanese: "Oroshiya"), of whom they were already aware through Dutch traders, the term "Red Ezo" fell into disuse.
* The band Ezo