Nishikunihara Reiko is a Japanese idol singer and a former member of SDN48's 1st Generation.
- Name: Nishikunihara Reiko (西国原礼子)
- Nickname: Rachel (レイチェル)
- Birthdate: November 24, 1977
- Birthplace: Miyazaki, Japan
- Blood Type: A
- Agency: AKS
Singles B-sides Participation
- Kodoku na Runner
- Eros no Trigger (Undergirls A)
- Ai yo, Ugokanaide (Rachel)
- Abazure (Undergirls B)
- Cachaca de Jihaku Suru (Undergirls B)
- Uekara Natsuko (Undergirls B)
- Owaranai Encore
- Graduating at age 34, Reiko was the oldest member of SDN48, thus surpassing the record previously held by Nakazato Ayami. She and Nakazato are the only two members to ever be in the group while in their 30s.
- Reiko is the only SDN48 member to record a solo while in the group (Ohori Megumi recorded her solo while still a member of AKB48, miray already had a solo career before joining SDN48, and Kojo Seara released three solo singles prior to joining the group).