Zoe (in Greek: Ζωή, Zōē, meaning "Life") (c. 978 – June 1050) reigned as Byzantine Empress alongside her sister Theodora from April 19 to June 11, 1042. In addition, she was also enthroned as the Empress Consort to a series of co-rulers beginning with Romanos III in 1028 until her death in 1050 whilst married to Constantine IX.

Zoe was one of the few Byzantine empresses who was Porphyrogenita, or "born into the purple" (that is, she was born to a reigning emperor). She was the second daughter of Constantine VIII and Helena, daughter of Alypius. Her father had become co-emperor in 962, and sole emperor in 1025. His reign as sole emperor lasted for only three years, from December 15, 1025 to November 15, 1028.

Her position as an eligible imperial princess saw her considered as a possible bride for the Holy Roman Emperor in the west, Otto III in 996. A second embassy sent in 1001, headed by Arnulf, Archbishop of Milan was tasked with selecting Otto’s bride from among Constantine’s three daughters. The eldest, Eudocia, was disfigured by smallpox, while the youngest, Theodora, was a very plain girl. Arnulf therefore selected the attractive 23-year-old Zoe, to which her uncle, Basil II agreed. in January 1002 she accompanied Arnulf back to Italy, only to discover when the ship reached Bari that Otto III had died, forcing her to return home. Another opportunity arose in 1028, when an embassy from the Holy Roman Empire arrived in Constantinople with a proposal for an imperial marriage. Constantine VIII and the fifty-year-old Zoe rejected the idea out of hand when it was revealed that the intended groom Henry, the son of Conrad II was only ten years old.