Peter Mazur (born Vienna, Austria, 11 December 1922; died Lausanne, Switzerland, 15 August 2001[1]) was an Austrian-born, Dutch physicist and one of the founders of the field of non-equilibrium thermodynamics.

In 1951, Mazur obtained his doctorate under the direction of Sybren de Groot with a thesis entitled, "Thermodynamics of Transport Phenomena in Liquid Helium-2".

Under the direction of de Groot and Mazur, the institute grew substantially and eventually established the Lorentz Chair, a prestigious special professorship.

Mazur served on the boards of the International Union of Pure and Applied Physics (1966–84) and the Dutch Foundation for Fundamental Research of Matter (1970–85).

Significant results included the derivation of the Langevin equation with Irwin Oppenheim and the classic paper on harmonic oscillator systems by George Ford, Mark Kac, and Mazur, which was published in the Journal of Mathematical Physics (in 1965).

And Mazur, Wim van Saarloos, and Carlo Beenakker developed an algebraic method around 1982 to successfully describe hydrodynamic interactions between arbitrary numbers of particles using induced forces.

From 1994 to 2000, Mazur, together with J. Miguel Rubi, used the method of internal degrees of freedom to describe fluctuations in the context of nonequilibrium thermodynamics.