The book collections of the convents and schools of regular Lateran canons in the lands of the Grand Duchy of Lithuania represent a rich cultural heritage that has survived to modern times. After its abolition by the Russian authorities, the long-existing diocesan communities of canons disappeared. However, in 1629, the Krakow Congregation (Corpus Christi) was established, uniting monasteries from the territory of the Polish-Lithuanian Commonwealth and the Grand Duchy of Lithuania. This congregation included monasteries such as Kurozwęki, Kraśnik, Sucha and new facilities in Lithuanian territories. The foundations of canonical convents date back to various years, starting from 1619 with the monastery in Bychów founded by the Grand Hetman of Lithuania, Jan Karol Chodkiewicz, to subsequent foundations in Krzemienica and Słonim. All these convents operated until around 1845, when they were closed down by the Russian authorities. The canons placed great emphasis on reading and writing. The libraries of canonical convents contained book collections of various sizes and condition, but their content was similar. Canonical libraries housed both clerical and secular works, with an emphasis on sermon and theological literature. Canons did not remove banned books from libraries. The libraries also included works of fiction, literary collections included works by both classics and contemporary authors. In terms of language, Latin dominated, although there were also books in Polish and other foreign languages. Research on the collections of regular canons in the territories of the Grand Duchy of Lithuania remains a subject of interest to scientists, and their detailed analysis will allow for a better understanding of the cultural heritage of these regions.