The Marriage Charter of Empress Theophanu is the dower document for the Byzantine princess Theophanu. Written in Latin, the document was created after the marriage of Theophanu to Emperor Otto II in 972, which made her the empress of the Holy Roman Empire. The document was prepared by Otto II and exemplifies an instance of political and cultural contact between the Holy Roman Empire and the Byzantine Empire.

Theophanu was empress of the Holy Roman Empire by marriage to Emperor Otto II, and regent of the Empire during the minority of their son, Emperor Otto III, from 983 until her death in 991. She was the niece of the Byzantine Emperor John I Tzimiskes. She was known to be a forceful and capable ruler. Her status in the history of the Empire in many ways was exceptional. According to Wilson, "She became the only consort to receive the title 'co-empress', and it was envisaged she would succeed as sole ruler if Otto II died without a son."