James Thomas Clack (October 26, 1947–April 7, 2006) was an American football guard in the National Football League. He played for 11 seasons between 1971 and 1981. He died of heart failure in 2006, after a four-year battle with cancer. Clack graduated from Wake Forest University. He began his career with the Pittsburgh Steelers, and he was part of two Super Bowl championship teams in 1974 and 1975. In April 1978, the Steelers traded Clack (along with wide receiver Ernie Pough to the New York Giants in exchange for offensive lineman John Hicks. Clack spent four seasons with the Giants.