Hiroyuki Tamakoshi is a Japanese manga artist born on September 1, 1970, in Osaka Prefecture. He graduated from the Osaka campus of the Yoyogi Animation School, and after receiving an honorable mention at Kodansha's 45th Newcomer Manga Award for his work Arubaito ni Ikou, he made his professional debut with the series Boys Be...

Tamakoshi is best known as the illustrator of the long-running romantic comedy series Boys Be..., which was created in collaboration with writer Masahiro Itabashi. Serialized in Kodansha's Weekly Shōnen Magazine, the manga follows the romantic lives and coming-of-age experiences of young male protagonists through a series of often interconnected short stories. The franchise expanded across multiple sequel series, including Boys Be... 2nd Season, Boys Be... L CO-OP, and later installments such as Boys Be... next season and Boys Be... young adult. The original manga was adapted into a thirteen-episode anime television series produced by HAL Film Maker, which aired in 2000.

Beyond Boys Be..., Tamakoshi has created or contributed to a wide range of manga titles, many of which center on love comedies and romance. His other notable serialized works include Gacha Gacha, Do suru!? Paradise, Que Sera Sera, and A GIRLS. He has also collaborated on projects with other writers, providing the art for titles such as Makyou no Shanana (story by Hiroshi Yamamoto), Double Heroine (story by Hiroi Oji), and Kibo no Shima (story by Hiroya Moriyasu). In addition to original creations, Tamakoshi has worked on adaptations within the Mobile Suit Gundam franchise, including Mobile Suit Gundam UC: The Return of the Lion and Mobile Suit Gundam 0080: War in the Pocket.

In September 2022, Tamakoshi publicly announced that he had been diagnosed with stage three cancer and had begun a four-month course of chemotherapy, which temporarily paused his work on the Gundam 0080 manga adaptation. He expressed his determination to return to drawing as his health permitted. By December 2023, he announced that he would be taking a break from manga. Throughout his career, Tamakoshi has remained a consistent creator of romance and love comedy manga, with his artistic identity closely tied to the depiction of youthful relationships and humorous, often ecchi-tinged romantic situations. His long-running work on the Boys Be... franchise, spanning over two decades, represents a significant contribution to the romantic comedy genre in Japanese manga.