Medieval literature is a broad subject, encompassing essentially all written works available in Europe and beyond during the Middle Ages (that is, the one thousand years from the fall of the Western Roman Empire ca. AD 500 to the beginning of the Renaissance in the 14th, 15th or 16th century, depending on country). The literature of this time was composed of religious writings as well as secular works. Like modern literature, it is a broad field of study, from the utterly sacred to the exuberantly profane, touching all points in between. Works of literature are often grouped by place of origin, language, and genre.

Outside of Europe, medieval literature was written in Ethiopic, Syriac, Coptic, Japanese, Chinese, and Arabic, among many other languages.

In Western Europe, Latin was the common language for medieval writing, since Latin was the language of the Roman Catholic Church, which dominated Western and Central Europe, and since the Church was virtually the only source of education. This was the case even in some parts of Europe that were never Romanized.

In Eastern Europe, the influence of the Eastern Roman Empire and the Eastern Orthodox Church made Greek and Old Church Slavonic the dominant written languages.

In Europe the common people used their respective vernaculars. A few examples, such as the Old English Beowulf, the Middle High German Nibelungenlied, the Medieval Greek Digenis Acritas, the Old East Slavic Tale of Igor's Campaign, and the Old French Chanson de Roland, are well known to this day. Although the extant versions of these epics are generally considered the works of individual (but anonymous) poets, there is no doubt that they are based on their peoples' older oral traditions. Celtic traditions have survived in the lais of Marie de France, the Mabinogion and the Arthurian cycles. Another host of vernacular literature has survived in the Old Norse literature and more specifically in the saga literature of Iceland.

A notable proportion of medieval literature is anonymous. The lack of information about authors is due in part to the paucity of documents from this period but also to a medieval conception of the author's role which differs considerably from modern views on authorship (which come from the Romantics). Medieval authors often deeply respected classical writers and the Church Fathers and tended to retell and embellish stories they had heard or read rather than invent new stories. And even when they did invent, they often claimed to be handing down something from an auctor instead. In this light, the names of the authors themselves seemed much less important, and as a result many important works were never properly attributed.

Theological works were the dominant form of literature typically found in libraries during the Middle Ages. Catholic clerics were the intellectual center of society in the Middle Ages, and it is their literature that was produced in the greatest quantity.

Countless hymns survive from this period (both liturgical and paraliturgical). The liturgy itself was not in fixed form, and numerous competing missals set out the mass in varying orders. Religious scholars such as Anselm of Canterbury, Thomas Aquinas, and Pierre Abélard wrote lengthy theological and philosophical treatises, often attempting to reconcile the teachings of the Greek and Roman pagan authors with the doctrines of the Church. Hagiographies, or "lives of the saints", were also frequently written, as an encouragement to the devout and a warning to the wayward.