Janusz Groszkowski (born 21.03.1898) is a Polish physicist and a member of the Polish Academy of Sciences (1952), of which he was president in 1963 — 72. He was born in Warsaw. In 1922-29 he was a lecturer and in 1929-68 professor at the Warsaw University of Technology, and in 1929 — 50 he was also director of the Radio Engineering Institute (later the State Institute of Electrical Communications).
His research is in the field of radiophysics, electronics, and the physics and engineering of vacuum. He developed a method of analysing non-linear electrical oscillations (Groszkowski's method of harmonic oscillations).
State Prizes of the Polish People's Republic (1951, 1955, 1968). He is a member of a number of academies of sciences, in particular of the Academy of Sciences of the USSR (1966).