Tadamasa Hayashi (? ??, 1853–1906) was a Japanese art dealer who introduced traditional Japanese art such as ukiyo-e to Europe.
Tadamasa was born to the Nagasaki family of physicians.
When he was still a child, he was adopted into the Hayashi family, an upper-class samurai family of Toyama-han.
He then attended the University of Tokyo.
In 1878, he went to Paris as a translator to seek a new life abroad.