The Vatican Apostolic Library (Latin: Bibliotheca Apostolica Vaticana), more commonly called simply the Vatican Library, is the library of the Holy See, currently located in Vatican City. It is one of the oldest libraries in the world and contains one of the most significant collections of historical texts. Formally established in 1475, though in fact much older, it has 75,000 codices from throughout history.

Scholars have traditionally divided the history of the library into five periods:

• Pre-Lateran. The initial days of the library, dating from the earliest days of the church, before it moved to the Lateran Palace.
• Lateran. Lasted until the end of the 13th century and the reign of Pope Boniface VIII.
• Avignon. This period saw a great growth in book collection and record keeping by the popes who were in residence in southern France in Avignon between the death of Boniface and the 1370s when the Papacy returned to Rome.
• Pre-Vatican. From about 1370 to 1446, the library was scattered, with parts in Rome, Avignon and elsewhere.
• Vatican. Starting around 1448, the library moved to the Vatican and a continuous history begins to the present time.