John Frederick Hencken (born May 29, 1954) is an American former competition swimmer for Stanford University, three-time Olympic champion, and former world record-holder primarily in the 100 and 200 meter breaststroke events.

[1] Hencken was born in Culver City, California, and began swimming to recover from an operation he had to remove a growth behind his knee.

By 1971, he did much of his more intensive training and competition with the demanding Santa Clara Swim Club, about ten miles Northeast of Cupertino.

[8] Hencken attended and swam for Stanford University under Hall of Fame Coach Jim Gaughran beginning in 1972, majoring in general engineering and product design, and graduated in 1977.

[4][11] Four years later at the 1976 Summer Olympics in Montreal, Canada, Hencken won a gold medal in the 100-meter breaststroke with a world record time of 1:03.11.