Glenn McCarthy, American businessman, founded the Shamrock Hotel (died 1988)

Glenn Herbert McCarthy was an American oil tycoon. The media often referred to him as "Diamond Glenn" and "The King of the Wildcatters". McCarthy was an oil prospector and entrepreneur who owned many businesses in various sectors of the economy. McCarthy founded the Shamrock Hotel in Houston, which garnered him national fame and inspired the fictional character Jett Rink in Edna Ferber's 1952 novel Giant which, in 1956, became a film, which starred James Dean in the role.

The Shamrock was a hotel constructed between 1946 and 1949 by wildcatter Glenn McCarthy southwest of downtown Houston, Texas next to the Texas Medical Center. It was the largest hotel built in the United States during the 1940s. The grand opening of the Shamrock is still cited as one of the biggest social events ever held in Houston. Sold to Hilton Hotels in 1955 and operated for over three decades as the Shamrock Hilton, the facility endured financial struggles throughout its history. Hilton Hotels sold the hotel to the Texas Medical Center in 1985 and was demolished in 1987. The former hotel site is now campus locations for Texas A&M Institute of Biosciences and Technology and DeBakey High School for the Health Professions.