Oh Eun-seok ([o.ɯn.sʌk̚]; born 2 April 1983) is a South Korean sabre fencer.
Oh won gold in team sabre and silver in individual sabre at the 2003 Junior World Fencing Championships in Trapani, Italy.
At the 2007 FIE World Championships he won the bronze medal in the men's individual sabre category after losing to four-time Olympic champion and ten-time world champion Stanislav Pozdnyakov of Russia 12–15 in the semifinals.
Oh qualified for the 2008 Beijing Olympics for the individual sabre competition. On August 12, 2008, he won his first round 15–8 win against Dmitri Lapkes of Belarus, but ultimately had a 15–11 loss to eventual silver medalist Nicolas Lopez of France in the round of 16. He finished 13th.
At 2012 London Olympics, he participated as substitute for the team sabre competition. Despite not getting his chance for participating in quarterfinal match against Germany, and semifinal match against Italy, he came out on final match against Romania on 8th bout. He faced Alexandru Sirițeanu, who came out as substitute for the Romanian side. The bout finished in just 14 seconds, when Oh accumulated 5 points for the Korean side, while conceding 1 point. Ultimately, he won gold medal along with his teammates Gu Bon-gil, Won Woo-young, and Kim Jung-hwan.
2007 World Fencing Championships, Individual sabre
2012 Summer Olympics, Team sabre