Jerzy Ksawery Franciszek Sosnowski (Lemberg, Austrian Galicia, 3 December 1896 – 1942, 1944, or 1945, in Poland or the Soviet Union) was a Major in Section II ("Dwójka") of the Polish General Staff and a Polish spymaster in the Weimar Republic and Nazi Germany (1926–1934), where he used the pseudonyms Georg von Nałęcz-Sosnowski and Ritter von Nalecz.
In the Soviet Union, he was known as Jurek Sosnowski, and some sources call him Stanislaw Sosnowski.