Olivia Hack is an American voice actress recognized for her work in anime dubbing, with one of her prominent roles being Ninny Spangcole in the 2020 anime film Burn the Witch. In this adaptation of Tite Kubo's manga, she provides the English voice for the character, a witch and member of the pop duo Cecile Die Twice who works for Wing Bind in Reverse London. Her casting in the role was noted for continuing a pattern of voicing blonde-haired characters with pigtails, referencing her earlier on-screen role as Cindy Brady.

Hack's career in voice acting spans several decades, beginning in the 1990s. Her extensive filmography includes a significant amount of work dubbing Japanese anime series and films into English. A substantial early credit in this field was her role as Mao Jahana and Irene in the 50-episode series Blood+, which aired from 2005 to 2006. She also provided voices for various characters in the 2003 version of Astro Boy and for Abbey Windsor in Mobile Suit Gundam SEED Destiny and its 2024 film, Mobile Suit Gundam SEED Freedom. Additional anime credits include the series Dragon Pilot: Hisone and Masotan.

Beyond anime, Hack is widely known for her voice roles in Western animation. She is perhaps most recognized for her long-running role as Rhonda Wellington Lloyd in the Nickelodeon series Hey Arnold!, a part she played for over 40 episodes and reprised for the subsequent movies. Another of her most celebrated performances is Ty Lee in the critically acclaimed series Avatar: The Last Airbender. She has also been the voice of Cloe in various Bratz animated series, films, and video games for many years. Her other voice work includes roles in Family Guy, Star Wars: The Clone Wars, and Open Season 2.

Throughout her career, Hack has had recurring collaborations with several fellow voice actors. Her frequent co-stars have included Adam Wylie, Tara Strong, and Sam McMurray, as well as actresses Lacey Chabert and Cree Summer, with whom she worked on projects like Bratz and various other animated productions. She has also worked with directors such as Matthew O'Callaghan on multiple projects.

Hack's achievements in voice acting have been recognized with two nominations for the Young Artist Award for Best Performance in a Voice-Over for her work on Hey Arnold! in 2000 and 2001. Her career began at a very young age; she appeared in her first commercial for Minolta when she was only eight months old and later gained on-screen recognition for playing Cindy Brady in The Brady Bunch Movie and its sequel in the mid-1990s.