The Nitta Clan ( 新田氏 , Nitta-shi ) was one of several large clans descended from the Seiwa Genji through the decendency of Minamoto no Yoshikuni, and ranks among the main enemies of the Shikken (rulers) of the Hojo Clan, and later the Ashikaga Shogunate.
The founder of the Nitta Clan was Minamoto no Yoshishige (1135 - 1202), who was the older brother of Minamoto no Yoshiyasu, the founder of the Ashikaga Clan.
Yoshishige was to a landowner in the Nitta District of the former Kōzuke Prefecture in present-day Gunma Prefecture. Yoshishige supported Minamoto no Yoritomo (1147 - 1199) in the Battle of Ishibashiyama of 1180 against the Taira Clan.
The Nitta Clan grew in importance in the early 13th Century, when they controlled Kōzuke Province, with little interference from Kamakura, the capital of the Kamakura Shogunate, as their ancestor, Minamoto no Yoshishige did not support the main branch of the Minamoto in the Genpei Wars a century earlier.
In the 1330s, Nitta Yoshisada led his clan and a number of other Minamoto vassals against the Shikken (rulers) of the Hojo Clan. They succeeded, in June 1333, in destroying the Bakufu buildings in Kamakura .
The Nitta Clan played an important role once again by allying with the Date Clan and the Nanchō (Southern Court) during the Nanboku-cho Wars of the late 14th Century.