Tsuyoshi Yoshioka is a Japanese novelist and the original creator behind the light novel series Wise Man's Grandchild. He is recognized as the author of the story that began as a web novel and was later adapted into a published light novel series, a manga, and an anime television series.

Yoshioka was born in Kobe, Japan. His most notable and credited original work is Wise Man's Grandchild, which he authored as a web novel on the user-generated novel publishing website Shōsetsuka ni Narō, where it began serialization in January 2015. The story follows a young man who is reincarnated into a magical world and raised by a powerful sage named Merlin. The web novel's popularity led to its acquisition by the publisher Enterbrain, which began releasing the series in print under its Famitsu Bunko imprint starting in July 2015. As of the latest available information, the light novel series has been collected into seventeen volumes.

The success of the light novel also led to a manga adaptation. Illustrated by Shunsuke Ogata, the manga began serialization on Kadokawa Shoten's Young Ace Up website in March 2016 and has been compiled into numerous tankōbon volumes. The story was subsequently adapted into an anime television series. In the production of the Wise Man's Grandchild anime, Tsuyoshi Yoshioka is formally credited as the creator of the original story. His work falls within the isekai and fantasy genres, a popular category in contemporary Japanese light novels and anime that involves characters being transported to or reborn in another world.

While Yoshioka is primarily known for this single major work, his career is significant as an example of the modern Japanese publishing pathway where successful online web novels are discovered by commercial publishers and transformed into multi-platform media franchises. This trajectory, beginning on a free website and culminating in a televised anime adaptation, represents a common but notable route for new authors in the Japanese entertainment industry.