Irene Ducaena (1066 – February 19, 1133) was the wife of Byzantine emperor Alexius I Comnenus, and the mother of the emperor John II Comnenus and the historian Anna Comnena.

Irene was born in 1066 to Andronicus Ducas and Maria of Bulgaria {grandaugther of Ivan Vladislav of Bulgaria}. Andronicus was a nephew of Emperor Constantine X and a cousin of Michael VII. Irene married Alexius in 1078, when she was still eleven years old. For this reason the Ducas family supported Alexius in 1081 when a struggle for the throne erupted after the abdication of Nicephorus III. Alexius' mother, Anna Dalassena, a lifelong enemy of the Ducas family, pressured her son to divorce the young Irene and marry Maria Bagrationi, the former wife of both Michael VII and Nicephorus III. Irene was in fact barred from the coronation ceremony, but the Ducas family convinced the Patriarch of Constantinople, Cosmas I, to crown her as well, which he did one week later. Anna Dalassena consented to this only by forcing Cosmas to resign immediately afterwards; he was succeeded by Eustathius Garidas. Anna continued to live in the imperial palace and meddle in Alexius' affairs until her death 20 years later; Maria Bagrationi may have also lived in the palace, and there were rumours that Alexius carried on an affair with her. Anna Comnena vociferously denied this, although she herself was not born until December 1, 1083, two years later.

Irene was shy and preferred not to appear in public, although she was forceful and severe when acting officially as basilissa. She preferred to perform her household duties, and enjoyed reading hagiographic literature and making charitable donations to monks and beggars. Although Alexius may have had Maria as a mistress early in his reign, during the later part of his reign he and Irene were genuinely in love (at least according to their daughter Anna). Irene often accompanied him on his expeditions, including the expedition against Bohemund I of Antioch in 1107 and to the Chersonese in 1112. On these campaigns she acted as a nurse for her husband when he was afflicted with gout in his feet. According to Anna she also acted as a sort of guard, as there were constant conspiracies against Alexius. When she remained behind in Constantinople, she acted as regent, with Nicephorus Bryennius, Anna's husband, as a counselor.

Irene frequently suggested that Alexius name Nicephorus and Anna as his heirs, over their own younger son John. According to Nicetas Choniates, who depicts her more as a nagging shrew than a loving wife, she "...threw her full influence on the side of her daughter Anna and lost no opportunity to calumniate their son John...mocking him as rash, pleasure-loving, and weak in character." Alexius, preferring to create a stable dynasty through his own son, either ignored her, pretended to be busy with other matters, or, at last, lost his temper and chastized her for suggesting such things.

Irene nursed Alexius on his deathbed on 1118, while at the same time still scheming to have Nicephorus and Anna succeed him. Alexius had already promised the throne to John, and when John took his father's signet ring Irene accused him of treachery and theft. When Alexius finally died, she felt genuine grief, and wore the mourning clothes of her daughter Eudocia, whose own husband had died previously. However, she soon conspired with Anna and Nicephorus against John, but their plots were unsuccessful and both Irene and Anna were then forced into exile at the monastery of Kecharitomene, which Irene had founded a few years previously. It was not a harsh exile, and Irene lived there in peace, distributing food to the poor and educating young orphan girls.

Irene died on February 19, in either 1123 or 1133, most likely the latter. With Alexius she had seven children:
• Anna Comnena (1083-1153)
• Maria Comnena
• John II Comnenus (1087-1143)
• Andronicus Comnenus
• Isaac Comnenus
• Eudocia Comnenus
• Theodora Comnena