Keiko Aizawa is a Japanese actress and voice actress born on November 22, 1963, in Kanagawa Prefecture, Japan. She is affiliated with the theatre company Gekidan Subaru and has been active in the entertainment industry since the 1980s.

Aizawa's voice career encompasses a range of roles in anime, video games, and film dubbing. In anime television, her credits include Kanae Oikawa in Boogiepop Phantom (2000), Dr. Huang in the Saiyuki franchise, and Mrs. Campbell in the Emma: A Victorian Romance series. She also voiced Justina Valca in an episode of Last Exile (2003) and Kiyoko Ogasawara in Maria-sama ga miteru.

She is notably associated with the Sakura Taisen franchise. She voiced the character Isabelle "Grand Mere" Lilac in the 2001 video game Sakura Taisen 3: Is Paris Burning? and reprised the role in the original video animation series Sakura Taisen: École de Paris (2003) and Sakura Taisen: Le Nouveau Paris (2004). Her other anime film work includes a role as the mother of the protagonist in the 2004 feature film Steamboy and providing voice work for the 2006 film The Girl Who Leapt Through Time.

A significant portion of Aizawa's work is in Japanese dubbing of foreign films and television series. She has provided the Japanese voice for numerous actresses, including Sandra Bullock in Demolition Man, Bridget Fonda in Point of No Return, and Halle Berry in X-Men. She is particularly well-known for her long-term role as the voice of Dana Scully, originally played by Gillian Anderson, in the Japanese dubs of The X-Files television series and its subsequent feature films.

Her professional profile indicates a career focused on performance, with personal interests that include knitting summer hats and travel. Through her extensive work in both animation and live-action dubbing, Keiko Aizawa has established herself as a consistent presence in the Japanese voice acting industry.