Res Jost (10 January 1918 – 3 October 1990) was a Swiss theoretical physicist, who worked mainly in constructive quantum field theory.

Jost studied in Bern and at the University of Zurich, where he received his doctorate in 1946 under the supervision of the German physicist Gregor Wentzel.

[2] He then spent half a year with Niels Bohr in Copenhagen, where he introduced the Jost function into scattering theory.

From 1949 to 1955 he was at the Institute for Advanced Study in Princeton, where he worked with Walter Kohn, Joaquin Mazdak Luttinger and Abraham Pais among others.

[7] In 1984 Jost received the Max Planck Medal for outstanding achievements in theoretical physics.