John Michael Prausnitz (born January 7, 1928) is a professor of chemical engineering at the University of California, Berkeley, a position he has held since 1955.^[1]

Prausnitz received his Ph.D. in chemical engineering from Princeton University in 1955 after completing a doctoral dissertation titled "Liquid-phase turbulent mixing properties."^[2]

Prausnitz is responsible for many of the activity coefficient models used for the design of major chemical plants.^[3] He is a recipient of the National Medal of Science in the field of engineering for his work in engineering-oriented molecular thermodynamics.^[4]

He was elected a member of the National Academy of Engineering in 1979 for contributions to the thermodynamics of phase equilibria and its application to industrial process design.^[5] He was the founding editor of the Annual Review of Chemical and Biomolecular Engineering in 2010.^[6]