Gillian Anderson has contributed to the world of anime voice acting through her work on English-language dubs of major Japanese animated films. Her most prominent and widely recognized role in this field is providing the voice of Moro, the Wolf, in the English dub of Hayao Miyazaki’s epic fantasy film Princess Mononoke. The English version of this film was produced by Miramax and released in 1999, and it featured a high-profile cast of actors, with Anderson's role being one of the most noted. Her character, Moro, is a powerful 300-year-old wolf goddess and the adoptive mother of the film's heroine, San. At the time, Anderson’s casting was notable, as her fame from the television series The X-Files was a significant factor in the film's marketing.

Anderson continued her collaboration with Studio Ghibli, the famed animation house behind Princess Mononoke, by taking on a voice role in another of its productions. She joined the English dub cast for the 2011 film From Up on Poppy Hill, directed by Hayao Miyazaki’s son, Goro Miyazaki. In this coming-of-age story set in 1960s Yokohama, she voiced a character, adding to her relatively small but significant body of work in anime.

Beyond anime-specific productions, Anderson has an established career in voice acting for Western animation, including other notable roles that show her range. She voiced the villainous Cat in Aardman Animations’ stop-motion musical special Robin Robin, released on Netflix in 2021. For this role, she performed both speaking and singing lines. The directors of the special noted that she was recording as Cat around the same time she was portraying Margaret Thatcher in the series The Crown, and she channeled some of that performance into the character. Her performance was also noted for its effective use of purring and snarling sounds. Anderson also has voice credits in animated shorts like Room on the Broom (2012) and long-running series such as The Simpsons, where she has appeared as a guest voice actor across multiple seasons. While these roles are not anime, they demonstrate a broader engagement with voice acting that complements her work in the genre.