Reiko Ōmori is a Japanese voice actress, singer, and entertainer born on March 21, 1984, in Hakodate, Hokkaido. She stands 152 cm tall and has blood type AB. Ōmori began her entertainment career after winning the Pure Girl Award at the 21st Horipro Talent Scout Caravan in 1996. She made her acting debut the same year as a guest on the drama series Kaseifu wa Mita! During her early career, she performed under the stage name Aihara Rei before returning to her birth name, Reiko Ōmori. She is currently affiliated with the agency ADS.

Ōmori is best known for her debut voice role as the protagonist in the 1998 magical girl anime series Fancy Lala, also known by its full title Magical Stage Fancy Lala. In this production, she voiced the dual role of Miho Shinohara, a nine-year-old girl who dreams of becoming a manga artist, and her transformed fifteen-year-old idol persona, Fancy Lala. This role marked her first and most prominent credit as a voice actor. Another significant anime voice role was as Julie in the series Kaleido Star, which aired from 2003 to 2004.

Beyond voice acting, Ōmori is also a singer. For the series Fancy Lala, she performed the opening theme song La La La ~Kuchibiru ni Negai wo Komete~ and the ending theme song Trans-parence. She also sang the theme song Yume no Manto for the anime series Nyani ga Nyanda Nyanda Kamen.