Masato Uchishiba (内柴 正人, Uchishiba Masato, born 17 June 1978) is a Japanese judoka who won the gold medal in the men's under 66 kg division at the 2004 Summer Olympics in Athens, Greece, and at the 2008 Summer Olympics in Beijing, China.

Of winning the gold, he said, "I wanted this so badly I wouldn't have cared if it was my last fight ever," though his comments were officially translated as: "It is probably my last Olympics, that is why I am proud of my medal."

Starting in April 2010, Uchishiba coached the women's judo team at Kyushu University of Nursing and Social Welfare in Kumamoto Prefecture.

In November 2011, the school released Uchishiba from his coaching position following sexual harassment allegations.

[4][5] On 1 February 2013, Tokyo District Court has declined his claim as "impossible to trust", and sentenced him to 5 years in prison.