Motoko Kobayashi is a Japanese voice actor and singer from Tochigi Prefecture. She is affiliated with the talent agency Production Ace, having graduated from its associated training school. Kobayashi holds several qualifications, including a Fourth-Class Amateur Radio Operator's license, a Grade 2 Penmanship certificate, and a Grade 1 Japanese Word Processor Proficiency Test certificate.

Kobayashi is recognized for her role as Yoshino Naganohara, the playful and skilled kendo-practicing older sister of Mio Naganohara, in the 2011 anime television series Nichijou - My Ordinary Life. Another prominent role is as Ruri, one of the three main idols in the group Marronni ☆ Yell, in the 2018 promotional anime short Sakura no Chikai. For this project, she also performed insert songs and the theme song as part of the real-life idol group Marronni ☆ Yell.

In addition to these roles, Kobayashi has contributed her voice to a range of other anime and video game projects. Her other anime credits include minor roles in series such as R-15, Futari H, Dai-Shogun - Great Revolution, Back Street Girls: Gokudols, and World Witches Take Off!. She is also known for her work in the Kan Colle (Kantai Collection) franchise, voicing multiple destroyer characters including Hatsushimo, Hatsuharu, Wakaba, and Nenohi in various video games and the 2022 anime series Kan Colle: Let's Meet at Sea.