Guillermo Rojas, also known as Memo Rojas, is a Mexican voice actor and ADR director with a career in dubbing that began in 1995 in Cuernavaca. He started as an audio engineer before transitioning to voice acting, working with companies such as Intertrack and Grupo Video Digital. He is recognized for his work in the Latin American Spanish dubs of numerous anime series and films, contributing to the industry for over 25 years.

His extensive list of voice roles in anime includes Klaus Lunettes in Black Clover and the film Black Clover: Sword of the Wizard King, Ryosuke Takahashi in Initial D, and Renga in Naruto. He has also voiced characters in classic series such as the older Toguro, Seiryu, and Risho in Yu Yu Hakusho: Ghost Files, as well as Arbormon and Petaldramon in Digimon Frontier and IceDevimon in Digimon Tamers. While he is noted for his role as Boma in the anime Heat Guy J by one source, this casting is not consistent across all available information. Other anime credits include Griffin Minos in Saint Seiya: The Hades Chapter - Inferno, Gong Strong in Yu-Gi-Oh! Arc-V, and a role in Devilman Crybaby. His work also extends to films, such as the Mexican dub of Mazinger Z: Infinity and a role as a doctor in the dub of Grave of the Fireflies.

In addition to acting, Rojas has frequently taken on the role of ADR director for Mexican dubs of prominent anime. His directorial credits include One Punch Man, Kakegurui, and Yu-Gi-Oh! Arc-V. Beyond anime, his voice is widely known for characters in live-action series and films, such as Jack Bauer in 24, Michael Westen in Burn Notice (Operación Miami), and Briareos Hecatonchires in Appleseed. His performance as Dean Winchester in the later seasons of Supernatural garnered significant attention for its nuanced adaptation of the character's pivotal scenes.