Juliusz Osterwa, born Julian Andrzej Maluszek (23 June 1885 – 10 May 1947), was a renowned Polish actor, theatre director and art theoretician active in the interwar period.

[1] He was the founder of Theatre Reduta, the first experimental stage in Warsaw following Poland's return to independence at the end of World War One.

Osterwa began his Warsaw career at the age of 33 by staging the works of Poland's revolutionary dramatists including Juliusz Słowacki, Stanisław Wyspiański, Stefan Żeromski, Jerzy Szaniawski, Kazimierz Przerwa-Tetmajer, and Cyprian Norwid.

In 1931 Osterwa settled back in Warsaw and a year later, assumed the role of a director at the grand Juliusz Słowacki Theatre in Kraków.

Following the 1939 invasion of Poland by Nazi Germany and the Soviet Union, Osterwa was active in the underground education but also became ill.