Nishio Tadasaka (西尾 忠受, May 16, 1821 – August 31, 1861) was a daimyō in late-Edo period Japan, who ruled Yokosuka Domain in Tōtōmi Province.
When Tadakata retired from public life in 1843, Tadasaka became daimyō and head of the Nishio clan.
With regards to the administration of his own domain, he helped place its finances on a more stable footing by encouraging the cultivation of green tea and the increased production of lumber.
Tadasaka died on August 26, 1861, at the Nishio clan residence in Soto-Sakurada, Edo, at age 40.
His grave is located at the Nishio clan temple of Ryumin-ji in what is now part of the city of Kakegawa, Shizuoka.