Yoshihiro Hamaguchi (?? ??, Hamaguchi Yoshihiro, June 23, 1926 – August 9, 2011) was a Japanese freestyle swimmer.
He represented Japan at the 1952 Summer Olympics in Helsinki, Finland.
There, he won a silver medal as a member of the 4 × 200 m freestyle relay team, alongside Toru Goto, Hiroshi Suzuki and Teijiro Tanikawa.
Also competed in the 100m freestyle advancing to the semifinals, missing the finals by a narrow margin.
After retiring he debuted as an actor in the 1955 film Buruuba as a Japanese version of Tarzan.
He also appeared in the TV Show Shonen Jet, a detective adventure show made by Kadokawa Pictures.