Yoo Nam-seok (Korean: 유남석; Hanja: 劉南碩; born 1 May 1957) was the 7th President of the Constitutional Court of Korea since 21 September 2018 to 10 November 2023.

Born in Mokpo, Jeonnam Province of South Korea, Yoo Nam-seok graduated from Seoul National University college of law.

He passed the 23rd National Bar Exam [ko] in 1981 and completed the Judicial Research and Training Institute in 1983 to be a judge.

He expressed his view that conscientious objectors should be allowed to be granted the opportunity for alternative military service instead of being punished on his paper titled ‘Legal Review on Conscientious Objectors’ during his military service as an army legal officer in 1985.

He was appointed as Constitutional Court Justice directly by President of South Korea Moon Jae-in on October 19, 2017, and sworn in on November 13, 2017.