Numazu Domain (沼津藩 Numazu-han?) was a feudal domain under the Tokugawa shogunate of Edo period Japan located in Suruga Province. It was centered on Numazu Castle in what is now the city of Numazu, in modern-day Shizuoka Prefecture.
In 1601, Ōkubo Tadasuke, a 5000 koku hatamoto was rewarded by Shōgun Tokugawa Ieyasu for his efforts at the Battle of Sekigahara, where he stopped an advance by Toyotomi forces under the famed Sanada Yukimura, by elevation to the rank of daimyō. He was assigned the territory of Numazu, to the east of Sunpu, to be his domain, with revenues of 40,000 koku. However, when he died without heirs in 1617, the domain reverted to the Tokugawa Shogunate.
The domain was revived in April 1777, when the former wakadoshiyori Mizuno Tadatomo was transferred from Ohama Domain in Mikawa province, and assigned revenues of 20,000 koku. He rebuilt Numazu Castle in 1780, and his revenues were increased by 5,000 koku in 1781 when he assumed the post of rōjū . He received another 5,000 koku increase in 1785.