Anna (fl. 720–740) was the wife of Artabasdos, one of two rival Byzantine Emperors in a civil war which lasted from June, 741 to November, 743. The other Emperor was her brother, Constantine V.
Anna was a daughter of Leo III the Isaurian and his wife Maria. She was a sister of Constantine V. They had two sisters named Irene and Kosmo. Their names and place of burial were recorded in De Ceremoniis by Constantine VII. However nothing else is known of them.
The throne of the Byzantine Empire was unstable in the early 710s. Justinian II had been deposed and executed in 711. His deposition was followed by the brief reigns of Philippikos (711–713), Anastasios II (713–715) and Theodosios III (715–717). All three were elevated to the throne after coup d'états by factions of the Byzantine army.
Under this conditions two military commanders sought each other as allies. According to the chronicle of Theophanes the Confessor, Leo, strategos of the Anatolikon Theme and Artabasdos, strategos of the Armeniac Theme, formed an alliance in 715. Their goal was the eventual deposition of Theodosios and elevation of Leo to the throne. The alliance was sealed with the betrothal of Anna to Artabasdos.