Antonius "Anton" Johannes Geesink (born April 6, 1934) is a Dutch 10th dan judoka. He is a three-time World Judo Champion (1961, 1964 and 1965) and Olympic Gold Medalist (1964). He was 6'7" (2.01m) tall and at one time weighted 320 pounds (145 kg). He was born in Utrecht.
Geesink first participated in the European Championships in 1951, and placed second in his category. The following year, he won his first European title. Through to 1967, twenty more European titles followed. At the 1961 World Championships, Geesink became World Champion in the open class, defeating the Japanese, who had won all World Championship titles up to that point. Judo debuted as an official sport at the 1964 Summer Olympics, which were held in the sport's home country, Japan. Although Japan dominated three of the four weight divisions (light, middle and heavy), Anton Geesink won the final of the open weight division, defeating Akio Kaminaga in front of his home crowd. After winning the 1965 World Championships and a last European title in 1967, Geesink quit competitive judo. Anton Geesink is the only living 10th dan grade kodansha recognized by the IJF but not by Kodokan. There are three living 10th dan kodanshas recognized by Kodokan: Toshiro Daigo, Ichiro Abe and Yoshimi Osawa.