Wim van Saarloos, Professor of Theoretical Physics at Leiden University, has been President of the Royal Netherlands Academy of Arts and Sciences (KNAW) since 1 June 2018. He combines his work as President with teaching and research at Leiden University.

Wim van Saarloos (born 1955) is a theoretical condensed matter physicist. He studied at Delft University of Technology. After obtaining his PhD in theoretical physics at Leiden University in 1982, he joined AT&T Bell Laboratories in the USA as a researcher in the Materials Science division.

He returned to Leiden University in the Netherlands in 1991. His research in theoretical physics focuses on statistical physics and condensed matter physics. In 2009 he became the full-time director of the Dutch national foundation for Fundamental Research on Matter (FOM), at that time the physics branch of the Netherlands Organisation for Scientific Research (NWO), the national science funding agency.

From June 2015 to autumn 2016, Van Saarloos led the transition of NWO to a new organisational structure. While in Leiden, Wim van Saarloos founded and served as the long-time director of the Lorentz Center (1997-2009), an international workshop centre in the sciences. He also chaired the national committee that in 2007 developed the national physics programme, leading the government to support physics and chemistry in the Netherlands.

Van Saarloos received the Descartes-Huygens Prize and Physica Prize for his work in soft condensed matter physics and pattern formation. He is well known for his research on front propagation into unstable states and wrote an authoritative review of this subject in 2003 (Front propagation into unstable states - Physics Reports 386 (2003) 29–222).