Jeong Han Kim (Hangul: 김정한; born July 20, 1962) is a South Korean mathematician. He studied physics and mathematical physics at Yonsei University, and earned his Ph.D in mathematics at Rutgers University. He was a researcher at AT&T Bell Labs, Microsoft Research, and was Underwood Chair Professor of Mathematics at Yonsei University. He is currently a Professor of School of Computational Sciences at Korea Institute for Advanced Study.
His main research fields are combinatorics and computational mathematics. His best known contribution to the field is his proof that the Ramsey number R(3,t) has asymptotic order of magnitude t2/log t. He received the Fulkerson Prize in 1997 for his contributions to Ramsey theory.
In 2008 he became director of the National Institute for Mathematical Sciences of South Korea, but he was discharged in 2011 after being accused of having allegedly misappropriated research funds. However he was found not guilty by prosecution's investigation.