John V. "Jack" Mara (March 21, 1908 – June 29, 1965) was a co-owner of the New York Giants, an American football team that plays in the National Football League. Jack was the son of Elizabeth "Lizette" (née Barclay) and Tim Mara and brother of Wellington, and served as the team's president for 24 years. He and Wellington inherited the team upon their father's death in 1959.
He graduated from Fordham University in 1930 with a law degree. However, he never became a practicing lawyer, instead joining the Giants as Vice President. He was promoted to President in 1941.
Jack Mara died at the age of 57 on June 29, 1965, of cancer at Memorial Hospital. He is buried at the Gate of Heaven Cemetery, Valhalla, New York. He was inducted into the New York Giants Ring of Honor in 2010.