Bill Dufries, also known as William Dufris, was an American voice actor and audiobook narrator recognized for his extensive work in animation, radio, and audio drama. He was born on February 1, 1958, and passed away on March 24, 2020. His career in audio began in London, where he appeared in several BBC Radio plays and collaborated with director Dirk Maggs on productions such as an audio drama of Spider-Man, in which he voiced the title role. These experiences led him to co-found the audio production company The Story Circle, Ltd in the UK. After returning to the United States, he founded Mind's Eye Productions and co-founded both Rocky Coast Radio Theatre and The AudioComics Company, serving as a producer, director, actor, and engineer on numerous projects.

While he was widely known for voicing the title character in the American English dub of the children's series Bob the Builder for its first nine seasons, Dufries also built a notable career in anime voice acting. He provided voices for several English dubs of anime films, often for productions released in the United Kingdom by Manga Entertainment. Among his most recognized anime roles is that of Arsène Lupin III in two Lupin the Third films. In the 1996 Manga Entertainment UK dub of the first television special, Lupin the 3rd: Bye Bye, Lady Liberty, he voiced the main character, who was renamed "Wolf" to avoid copyright issues with the literary character Arsène Lupin. He also voiced the character in the dub of the feature film Lupin the 3rd: The Mystery of Mamo.

Beyond the Lupin series, his other anime voice work included roles in X, where he voiced Subaru Sumeragi, as well as Appleseed, Patlabor: The Movie, Patlabor 2: The Movie, New Dominion Tank Police, Venus Wars, and Angel Cop. In addition to his on-screen voice roles, Dufries was a highly acclaimed audiobook narrator. He was nominated for twelve Audie Awards from the Audio Publishers Association, winning in 2012 for Best Non-Fiction, and received 24 Golden Earphones Awards from AudioFile Magazine, which named him One of the Best Voices at the End of the Century. His narration work includes series such as The Pendragon Adventure, the Destroyermen series, and novels by authors like Neal Stephenson and John Scalzi. In 2018, he co-founded the audiobook company Dagaz Media.