Jakub Mortkowicz (25 March 1876 − 9 August 1931) was a Polish book publisher and bookseller.

Young Jakub graduated from junior high school in Radom.

Then, he was studying in Munich, Brussels and Antwerp,[1] where he graduated from Trading Academy and was a member of the Association of the Polish Students (Stowarzyszenie Polskich Studentów) and the Federation of the Socialist Youth (Związek Młodzieży Socjalistycznej).

After returning to Poland, he was working for Hyppolite Wawelberg and joined the Polish Socialist Party.

For socialist activity, Jakub Mortkowicz was prisoned in the Warsaw Citadel and then he was punished by forced migration to the Caucasus Mountains.