William Joseph Giambra (July 30, 1931 – March 2, 2018[1]) was an American boxer who faced and defeated most of the top contenders of his era.

Giambra was never given the opportunity to fight for the world middleweight championship, although he defeated Rocky Castellani twice, Castellani was given the opportunity to fight in an elimination bout for the world title against Sugar Ray Robinson.

On August 26, 1955 world middleweight champion Bobo Olson agreed to fight Giambra in a non-title match on national TV.

[2] Giambra continually beat the champion to the punch and rocked him many times throughout the figh, but at the end Olson was awarded a split decision win.

Giambra later became a referee and was the third man in the 1977 Jerry Quarry-Lorenzo Zanon heavyweight bout.