Kotomi Otsuka is a Japanese voice actress born in Ibaraki Prefecture on December 16, 1989. She is affiliated with the talent agency AIR AGENCY. Otsuka is a graduate of the Voice Actor Training Department at Tokyo Media Academy, now known as the Tokyo School of Voice Acting and International Academy.

Otsuka began her career in the 2010s, initially taking on small roles in series such as Iron Man, Black Butler II, and the short-form anime Kakko-Kawaii Sengen!, in which she voiced the character Manabu. She is known for her versatility, frequently voicing young boys and spirited child characters.

One of her early leading roles was as Naoya Yūki in the 2013 television anime Pupipō!. A significant recurring role came with the Cardfight!! Vanguard franchise, where she voiced the character Yamaji Karu across five seasons, starting with Cardfight!! Vanguard G in 2014. Her other anime credits include roles in High Score Girl, Fire Force, Crayon Shin-chan, Platinum End, Zom 100: Bucket List of the Dead, and Suicide Squad Isekai. In 2024, she took on the role of the protagonist Tokiyuki Hojo in the voice comic adaptation of The Elusive Samurai.

Beyond animation, Otsuka's work extends to video games, such as Blue Protocol, and dubbing for foreign films and live-action series. She has also performed on stage, appearing in an adaptation of Genius Bakabon's Dad as the character Bakabon. In addition to voice acting, her skills include singing and songwriting.