Kelli Kassidi is a pseudonym used by American voice actress Megan Hollingshead, who is primarily known for her extensive work in English-language dubs of anime series and video games. She began her voice acting career in 1993 and has been credited under several names, including Karen Thompson and Holli Pop, in addition to Kelli Kassidi.

Hollingshead's career is marked by a significant number of prominent roles in anime. One of her most recognized performances is providing the voices for both Mion Sonozaki and Shion Sonozaki in the psychological horror series When They Cry (Higurashi no Naku Koro ni). This dual role required her to portray the identical but distinct twin sisters, who are central characters in the series' complex narrative.

Beyond this role, her filmography includes many other well-known series. She is famous for her work as Nurse Joy and Cassidy in the long-running Pokémon anime during its first six seasons. She also voiced Mai Valentine in the initial seasons of Yu-Gi-Oh! Duel Monsters, Rangiku Matsumoto in Bleach, Shizune in Naruto, Re-l Mayer in Ergo Proxy, and Villetta Nu in Code Geass. Her career also extends into video games, where she has voiced characters such as Lenneth Valkyrie in Valkyrie Profile and Five in Drakengard 3.

Throughout her career, Hollingshead has frequently collaborated with various New York- and Los Angeles-based voice direction teams and studios, contributing to dubs for numerous series. Her work demonstrates a recurring presence in major anime franchises adapted for an English-speaking audience.