Hans J. van Ommeren Dekker (born January 18, 1947, in Amsterdam, Netherlands) is a Dutch theoretical physicist in the line of Dirk Polder, Ralph Kronig, and Nico van Kampen. His scientific work inter alia involves laser theory, path integrals in curved spaces, nonequilibrium statistical mechanics, dissipation in quantum mechanics, and hydrodynamic turbulence. He is director of the Private Institute for Advanced Study and professor emeritus at the Institute for Theoretical Physics of the University of Amsterdam.