| Event: | Men's 66 kg |
| Games: | 2016 Summer |
| Venue: | Carioca Arena 2 |
| Date: | 7 August 2016 |
| Competitors: | 34 |
| Nations: | 34 |
| Gold: | Fabio Basile |
| Goldnoc: | ITA |
| Silver: | An Ba-ul |
| Silvernoc: | KOR |
| Bronze: | Rishod Sobirov |
| Bronzenoc: | UZB |
| Bronze2: | Masashi Ebinuma |
| Bronzenoc2: | JPN |
| Prev: | 2012 |
| Next: | 2020 |
The men's 66 kg competition in judo at the 2016 Summer Olympics in Rio de Janeiro was held on 7 August at the Carioca Arena 2.
The gold and silver medals were determined by a single-elimination tournament, with the winner of the final taking gold and the loser receiving silver. Judo events awarded two bronze medals. Quarterfinal losers competed in a repechage match for the right to face a semifinal loser for a bronze medal (that is, the judokas defeated in quarterfinals A and B competed against each other, with the winner of that match facing the semifinal loser from the other half of the bracket).[1]
The medals for the competition were presented by Beatrice Allen, a Gambian member of the International Olympic Committee, and the gifts were presented by Yasuhiro Yamashita, International Judo Federation executive committee member.