Caterina Gattilusio (died July/August 1442) was the second wife of Constantine XI, the last Byzantine emperor, while he was still Despot of the Morea.
She was a daughter of Dorino of Lesbos and Orietta Doria. In 1440, Caterina was betrothed to Constantine Palaiologos. The Chronicle of George Sphrantzes records the author himself arriving in Lesbos Island on December 6, 1440 to collect Caterina and take her to her betrothed.
The marriage took place on 27 July 1441. However Caterina died within a year of her marriage. Death in childbirth has been suggested, as in the case of his previous wife Maddalena Tocco. Constantine never remarried.