Guilherme Marchi (born July 22, 1982) is a Brazilian professional bull rider on the Professional Bull Riders Built Ford Tough Series tour. He debuted late in the 2004 BFTS season, qualifying for his first-ever PBR World Finals and finishing 41st in the world. After finishing in the runner-up position for the PBR World Championship in three consecutive years, he won his first title in 2008. Statistically, Marchi is one of the most consistent riders on the tour, and he is a key member of the Brazilian PBR family of bull riders on the Built Ford Tough Series.
In 2005, Guilherme Marchi was the biggest threat to Justin McBride’s dream of being the PBR World Champion. McBride won, Marchi came in second, however, he was the PBR World Finals event winner that year. In 2006, Marchi once again failed to win when fellow Brazilian Adriano Moraes came from behind to claim the PBR World Championship, with Marchi placing second. Yet again, in 2007, Marchi finished the season in the number two position behind Justin McBride at the PBR Finals in Las Vegas.
In 2008, he dominated the PBR circuit, riding nearly 75% of his bulls, winning five events, and earning over $1.5 million (nearly three times as much as any other PBR rider) on his way to his first PBR season crown.
In March 2014, Marchi became the first bull rider to successfully complete 500 qualified rides in the PBR.
Marchi is 5 feet 9 inches (1.75 m) tall and weighs 180 lb. He is from Leme, São Paulo and is of Italian descent on his father's side. He currently resides in Ferris, Texas, USA. He is a right-handed rider. His career PBR earnings are just over $4 million. His special interests include soccer, team roping, and surfing.