Jules de Jongh is an American voice actress known for her work in animated television series, particularly in English dubs of anime and international co-productions. She is a graduate of the California Institute of the Arts and has been active in the voice acting industry since 1995.

De Jongh is recognized for several prominent voice roles in animated series with connections to the anime industry. She provided the English dub voices for the dual protagonists Yugo and Evangelyne in the first two seasons of Wakfu: The Animated Series, a French-Japanese co-production that blends anime-inspired visuals with European fantasy storytelling. She also voiced the title character Skunk in the Irish animated series Skunk Fu!, which drew heavily from martial arts and Eastern animation styles. In the Japanese anime series Ronja the Robber's Daughter, a production co-directed by Goro Miyazaki and co-produced by Polygon Pictures and Studio Ghibli, de Jongh voiced the Harpies. The English version of this series was released on Amazon Prime Video in 2017.

Beyond her anime-specific work, de Jongh has an extensive career in voice acting for other media. She voiced the protagonist Faith Connors in the video game Mirror's Edge and has performed numerous roles in the long-running children's series Thomas & Friends, where she served as the US voice for characters including Emily, Mavis, Rosie, and Caitlin across multiple films and episodes. Her additional animation credits include roles in Floogals, Boyster, Angelina Ballerina, and Lucky Fred.

De Jongh has also pursued work as a screenwriter, co-writing animated feature films including Spiked, which was selected for the official competition at the Annecy International Animation Film Festival, in addition to projects such as The Defects and Ellie and the Christmas Creep.