Kayoko Hayashi is a Japanese actress and voice actor born May 23, 1961, in Tokyo. She is affiliated with the theater company Gekidan Subaru. Hayashi graduated from the Department of Theatre at the College of Art, Nihon University. Her skills include sword fighting, which she lists as a special skill, as well as skiing and tap dancing, the latter of which she has practiced for over twenty years.

While Hayashi has worked extensively as a stage actress and in live-action television dramas, her voice acting career includes several notable anime roles. In addition to playing Sanae Someya in the series Human Crossing, she has appeared as Shizuka Oone in Kindaichi Case Files, Kotoyo Tanokura in Hurricane Polymar, and the mother of Zakuro in Tokyo Mew Mew. Her video game work includes a role in Shenmue II.

A significant portion of her voice work is in the field of dubbing for foreign films and television series. Her credits in this area include providing the Japanese voice for the character Ezme Cullen in the Twilight film series. She also dubbed roles for the Japanese releases of I Am Sam, About a Boy, A Bug's Life, and the television series ER, in which she voiced the character Jennifer. Her achievements are reflected in the breadth of her work across theater, television anime, and a substantial filmography of dubbed productions for both film and television.