Ryōta Ōsaka is a Japanese voice actor born on August 2, 1986, in Tokushima Prefecture. He is affiliated with the talent agency Early Wing and has been active in the industry since his debut in 2010. He is married to fellow voice actor Manami Numakura. In his role for the 2024 anime adaptation of the web novel Lockdown Zone: Level X, he voices the character Shūhei Murosaka.

Ōsaka's path to becoming a voice actor began after graduating from a local technical high school, when he moved to Tokyo with a friend who shared the same ambition. He studied acting for two years at Nippon Kogakuin Hachioji College before attending a voice actor training school. He subsequently passed an audition for Early Wing, marking the start of his professional career. His inspiration to enter the field came from admiring the work of voice actor Akira Ishida, particularly his roles in Tales of Eternia and Mobile Suit Gundam SEED.

His first leading role came in 2012 as Yuki Sanada in the anime Tsuritama. This performance was noted by director Kenji Nakamura for his "clear and colorless voice, like water," which was seen as well-suited for a protagonist. Since then, Ōsaka has built an extensive filmography, taking on a wide variety of main and supporting roles that demonstrate his versatility, ranging from cheerful and energetic characters to more serious or hot-blooded ones.

Among his most prominent roles are Sadao Maou in The Devil Is a Part-Timer!, Eijun Sawamura in Ace of Diamond, and Nariyuki Yuiga in We Never Learn. He has also lent his voice to critically acclaimed and popular series such as Attack on Titan, where he played Marco Bodt, Haikyu!! as Keiji Akaashi, and Demon Slayer: Kimetsu no Yaiba as the powerful adversary Gyutaro. His work extends to video games as well, with notable performances including Bennett in Genshin Impact.

In 2015, Ōsaka was honored with the Best Male Newcomer award at the 9th Seiyu Awards, a recognition of his early impact and promising future in the voice acting industry. Beyond acting, he has also hosted a radio show called ŌHana alongside fellow voice actor Natsuki Hanae.