Woon Sui Kut (Chinese: 温瑞吉; pinyin: Wēn Ruì Jí) was one of Singapore's longest-serving veteran swimming officials and a known figure in the international sporting arena. He was formerly a teacher at Victoria School.

Woon had officiated in numerous swimming events, including 10 Olympics swimming events in his lifetime. Woon served as the Secretary-General of the Singapore Swimming Association from 1964 - 1999, and as Vice-President of the Asian Swimming Federation (AASF), and a member of the international swimming body, Fédération Internationale de Natation[ (FINA).^[1] He was also known in the local swimming fraternity as "the Father of Swimming, Technical Officiating, Life Saving, Diving and Water Polo"^[2]

He was removed as an official from the 2004 Summer Olympics after signing off on a judge's report that failed to provide a reason for the disqualification of Aaron Peirsol in the 200 metre backstroke final.^[3]

Woon died at Changi General Hospital on 21 December 2013, at 4.34pm. He had died from complications after a fall at home a day before, and four days after returning from his officiating work at the 2013 Southeast Asian Games in Myanmar.