The Institute for Theoretical and Experimental Physics (ITEP; Russian Институт теоретической и экспериментальной физики) is a multi-disciplinary research center located in Moscow, Russia.

ITEP was established on December 1, 1945, initially carrying the name "Laboratory №3", with the purpose of conceiving a heavy water nuclear reactor and cosmic ray studies.

The employees are also active in teaching (at undergraduate and masters levels as well as doctorates) and regularly organize conferences, seminars and a winter school.

Other important theoretical physicists at the institute were Karen Ter-Martirosian and Lev Okun, both of whom were responsible for the selection of scientists during the Soviet Union, which at the time amounted to a strict "screening".

It is named after Russian physicist Isaak Yakovlevich Pomeranchuk, who together with Landau established the Theoretical Physics Department of the Institute.