Rio Sasaki is a Japanese voice actress and former child actress born on March 25, 2002, in Saitama Prefecture. She began her career as a child actress and was affiliated with the Himawari Theatre Group. Her early work includes a role in the 2005 television series Mushishi, where she provided the voice for the character Hinata.

Sasaki's career includes a range of voice roles in anime, video games, and dubbed foreign films. In the 2013 animated fantasy film Magical Sisters Yoyo & Nene, she voiced the character Aki. That same year, she returned to the Mushishi franchise to play Hinata in the television special Mushishi Tokubetsu-hen: Hihamukage.

She has a notable, long-standing association with the Fafner anime series. Her work in this franchise includes voicing Emery Almond in the Fafner Exodus television series. She later took on the role of Ruby Karma in Fafner THE BEYOND, a character who is the reincarnation of Emery Almond.

Beyond these anime roles, Sasaki's filmography demonstrates her versatility. She provided the Japanese voice for a young Elsa in the Disney film Frozen and for Sherry Birkin in the 2019 remake of the video game Resident Evil 2. Other credits include roles in the anime series Blue Period and Bunny Drop, as well as the film Rudolf the Black Cat.