Nozomi Masu is a Japanese voice actress and stage actress born on July 26, 1980, in Saitama Prefecture, Japan. Her height is 159 cm, and her blood type is documented as both A and O in different sources. She is a graduate of the Department of Arts at Toho Gakuen College of Drama and Music.

Masu began her voice acting career in the early 2000s, with one of her earliest anime roles being a classmate of Izumi in Digimon Frontier in 2002. Her early work included roles in series such as Princess Tutu and Galaxy Railway. Throughout the 2000s, she established herself as a versatile performer, taking on a wide range of supporting and recurring characters in numerous television anime.

Some of her most recognized voice roles include Ginko Murakami in the 2008 series Kure-nai, Haruka Kawashima in White Album, and Inori Hiiragi in Lucky Star. She is also well-known within the Magical Girl Lyrical Nanoha franchise, voicing both Alto Kureetta and Dieci in Magical Girl Lyrical Nanoha StrikerS and its subsequent series. Her other notable anime credits include Fujita Harumi in Shakugan no Shana II, Miku Manabe in Ga-Rei-Zero, Kosame in Girls Bravo, Fio Atkins in The Sacred Blacksmith, and Noche in Fushigiboshi no Futagohime Gyu!. Her filmography extends into the 2010s and beyond with roles in series such as Hyouka, Monthly Girls' Nozaki-kun, and World's End Harem.

Beyond anime, Masu has contributed her voice to video games, including roles in Mabino x Style and Brown Dust 2. She has also been active in stage theatre, performing in numerous productions with independent theatrical troupes. Her other professional activities include narration work for commercials and participation in radio dramas and drama CDs.

For a significant part of her career, Masu was represented by the talent agency Pro-Fit. In April 2022, following the closure of Pro-Fit's management business, she transitioned to the agency Raccoon Dog, where she continues her career.