Mizoguchi Naohiro (溝口直溥, January 27, 1819 – April 26, 1874) was the 11th daimyō of Shibata Domain in Echigo Province, Japan (modern-day Niigata Prefecture).
He was received in formal audience by Shōgun Tokugawa Ienari in 1832, and became daimyō in 1838 on his father's retirement.
In 1861, he was appointed one of the escorts for the trip by Princess Kazunomiya to Edo for her wedding to Shōgun Tokugawa Iemochi.
The following year, he was in the entourage of Shogun Tokugawa Iemochi's trip to Kyoto and was received in audience by Emperor Kōmei.
In 1867, he officially retired in favor of his son and in 1868 returned to Shibata, where he took the tonsure.