Mizoguchi Naoyasu (溝口直養, December 24, 1736 – August 18, 1797) was the 8th daimyō of Shibata Domain in Echigo Province, Japan (modern-day Niigata Prefecture).

As daimyō he attempted to put these theories into practice, imposing a strict fiscal reform over all opposition, cutting back severely on expenses and managed to repay a portion of the domain's huge outstanding debt.

On the other hand, the relieve growing unrest over high taxation, he also conducted land surveys, established warehouses for rural famine relief and continued flood control projects.

He also established a han school in 1772, but ordered that traveling lecture tours be made to various towns and villages to encourage education of the common people.

On the other hand, Naoyasu had an affair with a Nihonbashi geisha and even commission the noted bijinga Ukiyoe artist Kitao Shigemasa to make a painting of her, since his position would not allow him to visit her very often.