The library of the teacher and gymnasiarch of the Kyiv-Mohyla Academy Ivan Samoilovych (c. 1737–1783) is a little-studied aspect of the history of the KMA and an extraordinary phenomenon in the domestic historical library science. Until now, it has not been the subject of independent historical and library research. Samoilovich was the teacher of rhetoric, poetics, and German. The main source base for the study of his library is the registration list concluded after the death of the owner in 1783, which numbered 1,147 items, and old prints which are now stored in the Vernadsky National Library of Ukraine in the department of libraries’ and historical collections and in the collections of the rare books department. The bibliographic analysis of the library fund showed that the composition of the book collection reflects the professional activity of the owner and the range of his intellectual interests. The topics of the books cover a wide range of interests: editions of grammars, dictionaries, works used for translations from Latin and German, works on public speaking, works by ancient authors and European humanists of the Renaissance, works on philosophy, logic, theology, natural sciences, medicine, general and church history, pedagogy, library affairs, and fiction.