Guillaume Desmarchelier is a French voice actor who specializes in dubbing anime series and films into French. He is known for providing the French voices for a wide range of characters across numerous popular anime franchises.

His career encompasses significant roles in major series. He voices the character Shin in the series Battle Game in 5 Seconds and Riki Nendo in The Disastrous Life of Saiki K.: Reawakened. His repertoire includes a variety of other prominent titles. He is the French voice of Toji Fushiguro in Jujutsu Kaisen (season 2) and Tiziano in JoJo's Bizarre Adventure: Golden Wind.

Desmarchelier's voice work also extends to characters in The Eminence in Shadow as Quinton, Overlord IV as Fan Long, and Vinland Saga (season 2) as Blaireau for the Crunchyroll dub. Additional credits include roles in Drifting Dragons as Vadakin, The Ancient Magus' Bride (season 2) as Inuo, the film Dragon Quest Your Story as Bjorn, and the ONA series BASTARD!! -Heavy Metal, Dark Fantasy- as a werewolf.