Olivia Hack is an American actress and voice actress best known for providing the voice of Rhonda Wellington Lloyd in Nickelodeon's Hey Arnold!. She provided the voice for Ty Lee and additional characters across ten episodes of Avatar: The Last Airbender.
Hack is the daughter of renowned television director Michael Hack.
Hack's career as an actress began when she appeared in a commercial spot at eight months old and she later played Cindy Brady in the 1990s theatrical Brady Bunch films; Entertainment Weekly noted the authenticity of Hack's reprisal of the character for the films and the New York Daily News made positive comparisons of Hack's work to that of Susan Olsen's Cindy from the original television series.
On television, Hack has done voice work for Fillmore!, Bratz as Cloe, Family Guy, and Blood+, and has also made appearances in Star Trek Generations, Party of Five, and Gilmore Girls.
She is the second voice actor of Shion Uzuki in the Xenosaga series.
Hack used to own Salon Atmosphere in Long Beach, California.