Józef Celmajster (later Józef Niemirski) (born 27 December 1901 - 7 December 1968 in Warsaw, Poland) was a Polish physician of Jewish descent, first lieutenant of the Polish Army, chief of medical department of the Jewish Military Union (ŻZW) in the Warsaw Ghetto and OW-KB.
thumb|200px|Tombstone of Józef Celmajster in the Powązki Military CemeteryCelmajster, a graduate of the University of Wilno, participated in the 1939 Defensive War and the Warsaw Ghetto Uprising. Later deported to the German concentration camp Auschwitz and survived.
After World War II he worked as physician.