Pati Kremer (1867–1943) was a Russian revolutionary socialist and pioneer of the General Jewish Workers' Union in Lithuania, Poland and Russia (Bund).
Upon her release, she returned to Vilna, where she became a leading member and organizer of the Jewish Social-Democratic circle known as the 'Vilna Group', together with John Mill (1870–1952) and Arkadi Kremer (1865–1935).
Pati Kremer worked as editor and translator in the publishing house of Boris Kletskin (1875–1937), a Bundist.
During the German occupation of Vilna in the Second World War she became a leading figure in the city's Jewish ghetto, organizing and maintaining secret Yiddish libraries and clandestine meetings of the Bund.
When the ghetto was razed by the Germans in September 1943, Pati Kremer was among the many victims who were rounded up, transported to the Sobibor extermination camp and murdered.