Mizoguchi Naoatsu (溝口直温, June 20, 1716 – October 1, 1780) was the 7th daimyō of Shibata Domain in Echigo Province, Japan (modern-day Niigata Prefecture).

He was adopted as posthumous heir to Mizoguchi Naoharu in 1732 and received in formal audience by Shōgun Tokugawa Tsunayoshi the same year.

Although the domain suffered from fewer flooding disasters than under his predecessors, good harvests conversely drove the price of rice down, and the domain remained unable to free itself of debt.

Furthermore, in 1738, the domain was ordered to return the 83,400 koku of tenryō lands back to direct administration by the shogunate.

In 1748, the domain was ordered to assist the Korean embassy to Japan during its stay ate Kanagawa-juku on the Tōkaidō.