Kei Kobayashi is a Japanese voice actress from Tokyo, born on June 30, 1976. She is affiliated with the talent agency 81 Produce. Kobayashi has built a career characterized by versatility, contributing her voice to a wide range of anime series, video games, and foreign film dubs.

Her body of work in anime includes roles in various television series. She is known for voicing characters such as Chitto in Fantastic Children, Yuri Hongō in Burst Angel, and Shīna Lacerus in Tactical Roar. Her credits also include parts in long-running and popular series like Hamtaro, where she voiced Cappy-ham, and Inuyasha. In the franchise Rockman.EXE, she took on several roles, and she also contributed to the Slayers series.

Beyond anime, Kobayashi has an extensive career in voice-over dubbing for foreign content. She has provided the Japanese voice for characters in live-action productions, such as Anna Stern in the television series The O.C. and Alice Fletcher in Godless. Her dubbing work also extends to animated films, including roles in the Japanese-language versions of Hollywood movies like Inside Out and The Great Gatsby.

A notable recurring aspect of Kobayashi's career is her involvement in the Sylvanian Families franchise. In the 2017 anime series Sylvanian Families Mini Story, she voiced the character of Chocolate Usagi's grandmother. Her role as a maternal figure continued in subsequent series within the franchise, including Sylvanian Families Mini Story Clover and Sylvanian Families Mini Story Ivy, where she is credited with voicing the characters Catherine-san, Kuma Mother, and Patricia across these installments. Her work demonstrates a lasting connection to the gentle and family-oriented world of Sylvanian Families.