Walter Noll (January 7, 1925 – June 6, 2017) was a mathematician, and Professor Emeritus at Carnegie Mellon University.

In 1954, Noll earned a Ph.D. in Applied Mathematics from Indiana University Bloomington in 1954 under Clifford Truesdell.

[2] His thesis "On the Continuity of the Solid and Fluid States" was published both in Journal of Rational Mechanics and Analysis and in one of Truesdell's books.

[3] Noll thanks Jerald Ericksen for his critical input to the thesis.

[5] In continuum mechanics, Noll introduced the so-called principle of material objectivity,[6] which states that the constitutive laws governing the internal conditions of a physical system and the interactions between its parts should not depend on whatever external frame of reference is used to describe them.