Sansei is a Japanese and North American English term used in parts of the world to refer to the children of children born to ethnically Japanese emigrants (Issei) in a new country of residence, outside of Japan. The nisei are considered the second generation, while grandchildren of the Japanese-born emigrants are called Sansei. The fourth generation is referred to as yonsei. The children of at least one nisei parent are called Sansei; they are usually the first generation of whom a high percentage are mixed-race, given that their parents were (usually), themselves, born and raised in America.

Issei are Japanese immigrants to countries in North America and South America. The term is used mostly by ethnic Japanese. Issei are born in Japan; their children born in the new country are nisei ; and their grandchildren are sansei.