Ryō Naitō is a Japanese voice actor and stage actor born on June 22, 1974, in Osaka Prefecture. He is affiliated with the agency Ogipro THE NEXT. A graduate of the Yoyogi Animation Academy, Naitō began his career in the mid-1990s, with one of his earliest roles being in the 1996 anime Rurouni Kenshin. He is known for his versatile vocal range, capable of portraying characters from young boys to middle-aged men, and frequently utilizes his native Kansai dialect in performances.

Naitō has built a prolific career through numerous supporting and recurring roles in long-running and popular anime series. He is widely recognized for his portrayal of the earnest and somewhat hapless Tōta Matsuda in the psychological thriller Death Note. In the long-running sports franchise The Prince of Tennis, he voices the character Koharu Konjiki. Another significant role is that of Taiga Okajima in the action-comedy Assassination Classroom. He has also appeared in Yu-Gi-Oh! Duel Monsters as Ryūji Ōtogi, Hunter x Hunter as a member of the Zoldyck family's canine butler, Mike, and in Kill la Kill as Kusanosuke Yaguruma.

A notable aspect of Naitō's career is his long-standing collaboration with the gag comedy franchise Gag Manga Biyori (also known as Gyagu Manga Biyori). His work on this series is extensive, and he has voiced a wide array of characters across its multiple seasons, including the featured role of the famed haiku poet Matsuo Bashō in the series Masuda Kōsuke Gekijō Gag Manga Biyori GO. This role highlights his comedic timing and ability to bring historical figures to life in a humorous context. His other roles in the franchise include a narrator, a version of the Chinese folk hero八戒 (Bajie / Pigsy), and numerous incidental characters. Beyond these, his extensive filmography includes roles in series such as Cromartie High School, Hell Girl, and the film 5 Centimeters Per Second.