Megumi Yamaguchi is a Japanese actress and voice actress born on May 12, 1997, in Tokyo. She is affiliated with the Himawari Theatre Group, a talent agency known for representing child actors and performers. Her career in entertainment began at a young age; she debuted as a live-action actress in 2002, appearing in the television series First Love and subsequently featuring in numerous other television dramas and commercials. Her transition to voice acting started with her first anime role as Lulu in the 2008 series Michiko & Hatchin.

Yamaguchi has built a diverse portfolio of voice roles in anime, often playing main or supporting characters. One of her earliest prominent roles was as Koharu Nanakura in the long-running Aikatsu Stars! series, which began in 2016. That same year, she was cast as the shy and experienced character Hifumi Takimoto in the popular workplace comedy New Game!, a role she would reprise in its second season, New Game!!, and in related video games. Her other significant anime roles include Lynn Hughes in the fantasy series Wise Man's Grandchild, Muramasa in Z/X Code reunion, and Ao Manaka in the slice-of-life anime Asteroid in Love. More recently, she has voiced Mahoro Miyaji in the series Cue! and Hinako in The Fire Hunter.

In addition to her anime work, Yamaguchi's career as a voice actress extends to video games and dubbing foreign films. She has lent her voice to characters in games such as New Game! -The Challenge Stage!- and Cue!. Her dubbing work includes providing the Japanese voice for Isabelle in the film Hugo. Beyond voice acting, she has also been involved in music related to her anime roles, performing character songs and theme songs for series like New Game! and the multimedia project Hinabita♪. Her work often involves recurring collaborations with fellow cast members in long-running projects, such as the ensemble casts of New Game! and Cue!.