John Campbell is the professional alias used by American voice actor Gregory Abbey. He is known for his extensive work in English-language dubs of anime series, primarily during the late 1990s and 2000s, often in association with production companies such as 4Kids Entertainment, Central Park Media, and NYAV Post.

Abbey, born on December 15, 1970, is a graduate of Rutgers University. He adopted the pseudonym John Campbell for various voice-over roles, a common practice in the industry. Under this name, he is credited for the role of Chief Chujo Shizuo in the influential OVA series Giant Robo: The Day the Earth Stood Still. He also provided the voice for the character Goldymarg in the series GaoGaiGar: King of the Braves.

Beyond the John Campbell alias, his broader career as Gregory Abbey includes some of his most recognized performances. He is well known as the voice of Tristan Taylor in the long-running series Yu-Gi-Oh! Duel Monsters and its subsequent film appearances, and as the protagonist Yusei Fudo in Yu-Gi-Oh! 5D's. Another signature role, often credited under the alias Frank Frankson, is Raphael in the 2003 Teenage Mutant Ninja Turtles television series and its related video games.

His filmography also includes roles in other notable anime such as Berserk, Shaman King, and Sonic X, as well as voice work in animated series like Winx Club and video games such as the Ape Escape and Teenage Mutant Ninja Turtles series. This body of work, performed under his own name and his various aliases, establishes him as a prolific figure in English anime dubbing and animation voice-over from that era.