Ronald P. Toby (1942 — ) is an American historian, academic, writer and Japanologist.
Toby earned a doctorate in Japanese history from Columbia University in 1977.
As a university professor, Toby's teaching experience has included the University of Illinois at Urbana-Champaign, the University of California at Berkeley, Keio University, and the University of Tokyo.
Toby's academic specialization focuses on issues having to do with pre- and early-modern Japan. His book State and Diplomacy in Early Modern Japan demonstrates that during the so-called "closed country" period in the Edo era, Japan was never truly closed to the outside world.
Toby's published writings encompass 18 works in 33 publications in 3 languages and 794 library holdings.