Rosi Wolfstein (after 1948, Rosi Frölich: 27 May 1888 - 11 December 1987) was a German socialist politician.After the murder of her friend and mentor, the communist pioneer Rosa Luxemburg, she inherited Luxemburg's copious collection of papers, and devoted much time to organising the archive.
During the 1930s, with her partner Paul Frölich, Rosi Wolfstein worked on an important biography of Luxemburg.