Tadeusz Kamil Marcjan Żeleński (better known by his pen name, Tadeusz Boy-Żeleński; 21 December 1874 – 4 July 1941) was a Polish stage writer, poet, critic and, above all, the translator of over 100 French literary classics into Polish. He was a pediatrician and gynecologist by profession. A notable personality in the Young Poland movement, Boy was the enfant terrible of the Polish literary scene in the first half of the 20th century. He was murdered in July 1941 by the Germans during the Nazi occupation of Poland, in what became known as the massacre of Lwów professors.