Irene Lascarina (or Eirene Laskarina) (Greek: Ειρήνη Λασκαρίνα, Eirēnē Laskarina) was a daughter of Theodore I Laskaris, emperor of Nicaea and Anna Angelina. Her maternal grandparents were Emperor Alexios III Angelos and Euphrosyne Doukaina Kamaterina. Her sister Maria Laskarina married King Béla IV of Hungary.
Eirene first married the general Andronikos Palaiologos, and after his death became the wife of Theodore's designated successor, the future John III Doukas Vatatzes in 1212. With John III she had a son, the future Theodore II Doukas Laskaris. After the latter's birth, she fell from a horse and was so badly injured that she was unable to have any more children. She retired to a convent, taking the monastic name Eugenia, and died there in 1239, some fifteen years before her husband.
Eirene is much praised by historians for her modesty and prudence, and is said to have brought about by her example a considerable improvement in the morals of her nation.