John F. Carroll (1932 – 1969) is one of 17 known people in medical history to reach a height of 8 feet (2.4 m) or more. Carroll suffered from severe, 2-dimensional spinal curvature (Kyphoscoliosis) and acromegalic gigantism. He had a standing height of 244 centimeters (8 feet 0 inches) on October 14, 1959, but his height would have been 264 centimeters (8 feet 7¾ inches), assuming normal curvature of the spine. He was later measured at 239 centimeters (7 feet 10½inches) in 1968; he had shrunk in stature due to his worsening spinal condition.

Shortly before Carroll's death in 1968 his standing height was 234 centimeters (7 feet 8¼ inches). His corrected height was not recorded but may have been close to nine feet.

Carroll was born in Buffalo, New York, United States, and also known as the Buffalo Giant in medical literature. Carroll was third in stature only to Robert Wadlow and Willie Bud Rogan. His extraordinary growth started at the age of sixteen and continued until his death, despite extensive treatments at Mercy Hospital. At one point he grew seven inches in height in a matter of a few months. He was buried in Holy Cross Cemetery in Lackawanna, New York.

While in a hospital bed Carroll ran a campaign for Alderman of his district and lost by only a few votes.