The Alexiad (original Greek title: Ἀλεξιάς) is a medieval biographical text written around the year 1148 by the Byzantine historian Anna Comnena, daughter of Emperor Alexius I.

Within the Alexiad, she describes the political and military history of the Byzantine Empire during the reign of her father (1081-1118), making it one of the most important sources of information on the Byzantium of the High Middle Ages. As well as this, within the Alexiad, the First Crusade's interaction with the Byzantine Empire is documented (despite being written nearly fifty years after the crusade), which highlights the conflicting perceptions of the East and West in the early 12th century.

The text was written in a form of artificial Attic Greek, and it is one of only a few examples of a woman writing about the political and military history of her own country, and it is also a valuable source as to ascertain the Byzantine perception of the Crusaders.

Due to the relationship between Anna and Alexius Ι, strong bias problems exist, despite Anna's frequent attempts to establish her objectiveness. Nevertheless, she manages to leave disguised traces of criticism of a father she deeply admires. She cannot hide her aversion to the Latins (Normans and "Franks") whom she considers barbarians, the "barbarians" in general and the Armenians. She also fails to hide a deep hatred felt for her brother John II Komnenos. However, all this does not prevent her from expressing admiration for the virtues, abilities or even charm of several enemies of the Empire (including lethal ones like Robert Guiscard and his son Bohemund). From a modern reader's point of view, the description of military events and the Empire's misfortunes may seem exaggerated and stereotypical (partially due to Homeric influences). There is also much confusion regarding the names and ranks of foreigners (particularly of Seljuk Turks) and a few geographical and dating errors.