Byzantine studies is an interdisciplinary branch of the humanities that addresses the history, culture, demography, dress, religion/theology, art, literature/epigraphy, music, science, economy, coinage and politics of the Eastern Roman Empire. The discipline's founder in Germany is considered to be the philologist Hieronymus Wolf (1516–1580), a Renaissance Humanist. He gave the name "Byzantine" to the Eastern Roman Empire that continued after the Western Roman Empire collapsed in 476 AD. About 100 years after the final conquest of Constantinople by the Ottomans, Wolf began to collect, edit, and translate the writings of Byzantine philosophers. Other 16th-century humanists introduced Byzantine studies to Holland and Italy. The subject may also be called Byzantinology or Byzantology, although these terms are usually found in English translations of original non-English sources. A scholar of Byzantine studies is called a Byzantinist.

Byzantine studies is the discipline that addresses the history and culture of Byzantium (Byzantium ↔ Byzantine Empire, the Greek Middle Ages; Byzantium = Constantinople [as capital of the Byzantine Empire]). Thus the unity of the object of investigation ("Byzantium") stands in contrast to the diversity of approaches (= specializations) that may be applied to it. – There were already "Byzantine" studies in the high medieval Byzantine Empire. In the later Middle Ages, the interest in Byzantium (in particular the original Greek sources) was carried on by Italian humanism, and it expanded in the 17th century throughout Europe and Russia. The late 19th and early 20th centuries brought the formation of Byzantine studies as an independent discipline.

Greek-Hellenistic culture, Roman state traditions, Oriental influence and Christian faith, together with a relative unity of language and culture, constitute medieval Byzantium. The starting point of Byzantine history is usually taken to be the reign of Constantine the Great (306–337) and the foundation of Constantinople (330). The "East Roman" (or Late Antique) era of Byzantium begins at the latest with the division of the Roman Empire into a Western Roman Empire and an Eastern Roman Empire (395). This "Early Byzantine" period lasts until approximately 641 AD. Emperor Justinian I (527–65) reconquered Italy, north Africa, and southern Spain, but after the expansion of Islam (634/98) a reorganized Byzantium, now based on administration by Themes, was limited to the Greek-speaking regions of the Balkan peninsula, Asia Minor, and southern Italy; Latin was abandoned as the language of officialdom. This may be perceived as the "end of antiquity", and the beginning of the "Middle Byzantine" era.

This was also the era of Iconoclasm (717–843) and of the origin of the Holy Roman Empire (800). Under the Macedonian Dynasty (10th–11th centuries) Byzantium regained power against the Islamic and Bulgarian states, but the death of Emperor Basil II marked a turning point, with Byzantine power in Asia Minor and southern Italy suffering from the Battle of Manzikert (1071) and the rise of the Normans, respectively. A certain stability was achieved under the Comnenian Dynasty, at least until the Battle of Myriokephalon (1176). Internal conflicts facilitated the sack of Constantinople by the Crusaders (the Fourth Crusade of 1204) and the establishment of Latin states in the south Balkans.

The late period of the Byzantine Empire as a small state begins with the Palaiologos dynasty, which was particularly threatened by the advances of the Ottoman Empire and the economic influence of Venice and Genoa. An empire weakened in part through civil war suffered a severe blow when Thessalonica was captured in 1430, and finally fell to the Ottomans (Fall of Constantinople in 1453, and of Mistras in 1461). The Empire of Trebizond (1204–1461), founded in the wake of the Fourth Crusade, also forms a part of Byzantine history.

It is possible to distinguish between three levels of speech: Atticism (the literary language), Koine (the common language of the Hellenistic period), and Demotic (the popular language, and the forerunner of modern Greek). Thus a certain diglossia between spoken Greek and written, classical Greek may be discerned.

Major genres of Byzantine literature include historiography (both in the classical mode and in the form of chronicles), hagiography (in the form of the biographical account or bios and the panegyric or enkomion); hagiographic collections (the menaia and synaxaria), epistolography, rhetoric, and poetry. From the Byzantine administration, broadly construed, we have works such as description of peoples and cities, accounts of court ceremonies, and lists of precedence. Technical literature is represented, for example, by texts on military strategy. Collections of civil and canon law are preserved, as well as documents and acta (see "Diplomatics" below). Some texts in the demotic are also preserved.

There are currently three main schools of thought on medieval eastern Roman identity in modern Byzantine scholarship: 1) a potentially preponderant view that considers "Romanity" the mode of self-identification of the subjects of a multi-ethnic empire, in which the elite did not self-identify as Greek and the average subject considered him/herself as "Roman", 2) a school of thought that developed largely under the influence of modern Greek nationalism, treating Romanness as the medieval manifestation of a perennial Greek national identity, 3) a line of thought recently proposed by Anthony Kaldellis arguing that Eastern Roman identity was a pre-modern national identity.