Mladen Bestvina (born 1959) is a Croatian-American mathematician working in the area of geometric group theory. He is a Distinguished Professor in the Department of Mathematics at the University of Utah.
Mladen Bestvina is a three-time medalist at the International Mathematical Olympiad (two silver medals in 1976 and 1978 and a bronze medal in 1977). He received a B. Sc. in 1982 from the University of Zagreb. He obtained a PhD in Mathematics in 1984 at the University of Tennessee under the direction of John Walsh. He was a visiting scholar at the Institute for Advanced Study in 1987-88 and again in 1990-91. Bestvina had been a faculty member at UCLA, and joined the faculty in the Department of Mathematics at the University of Utah in 1993. He was appointed a Distinguished Professor at the University of Utah in 2008. Bestvina received the Alfred P. Sloan Fellowship in 1988–89 and a Presidential Young Investigator Award in 1988–91.
Bestvina gave an invited address at the International Congress of Mathematicians in Beijing in 2002. He also gave a Unni Namboodiri Lecture in Geometry and Topology at the University of Chicago.
Bestvina served as an Editorial Board member for the Transactions of the American Mathematical Society. He is currently an associate editor of the Annals of Mathematics and an Editorial Board member for Geometric and Functional Analysis, the Journal of Topology and Analysis,Groups, Geometry and Dynamics,Michigan Mathematical Journal,Rocky Mountain Journal of Mathematics, and Glasnik Matematicki.