John Hanley Cannady (September 5, 1923 – September 28, 2002) was an American football linebacker in the National Football League (NFL) for the New York Giants.

The first professional football player from Charleston, South Carolina, known as "Big John," he was the New York Giants' second-round draft pick in 1947 and played from 1947 to 1954.

A teammate of Frank Gifford from 1952 to 1954, Big John was a member of the New York Giants’ 1950 team that finished with a 10–2 record and tied for first place in the American Conference.

He was named to the South Carolina Athletic Hall of Fame in 1991, and to the Post and Courier’s list of South Carolina's 100 greatest athletes of the 20th century.

This biographical article relating to an American football linebacker born in the 1920s is a stub.