Saiko Moriya is a Japanese voice actress and stage actress affiliated with the talent agency Ken Production. She was born on December 16 in Tokyo's Setagaya ward and was raised in the city of Tokorozawa in Saitama Prefecture. Her physical attributes include a height of 162 cm and a blood type of O.

Moriya's path to voice acting was grounded in extensive stage experience. She graduated as part of the fifth intake of the Caramel Box Drama School in 2007 and later became a member of the Anemoi Program theater group. Her initial career was primarily focused on stage performance. The pivotal moment that led her to pursue voice acting was an encounter with the late Kenji Utsumi, the founder of Ken Production, at a stage event where she was working as a backstage staff member. Following this, she honed her vocal skills as a student in the 18th term of the voice actor training school School Duo. In April 2018, she officially joined Ken Production and began her career as a voice actress in earnest.

Her debut anime role was a housewife in the 2019 series How Heavy Are the Dumbbells You Lift?. Since then, she has built a diverse portfolio of supporting roles in numerous popular anime series. Some of her notable anime credits include Nambia in Attack on Titan The Final Season, a shopkeeper in BEASTARS, Anne Bonny in Fena: Pirate Princess, Ginko Shida in Osamake: Romcom Where The Childhood Friend Won't Lose, and a Japanese sweets shop worker in Laid-Back Camp Season 2. She has also lent her voice to characters in web anime such as the Spriggan reboot.

In 2024, Moriya was cast as Miss Fairlady in the television anime adaptation of Moriarty's Perfect Crime, marking a continuing role in a series. Her professional activities also extend to dubbing foreign films and television series, and providing narration for documentaries.

Beyond acting, Moriya holds a Level Pre-2 Kanji Proficiency certification. Her personal interests include watching theater and films, and she has a noted talent for giving massages and remembering faces and names. She maintains an active presence in both the voice acting and theater communities, continuing to participate in stage productions alongside her animation work.