Tommaso Fazello (Neo-Latin Fazellus, 1498 – 8 April 1570) was an Italian Dominican friar, historian and antiquarian.

He is the author of the first printed history of Sicily: De Rebus Siculis Decades Duae, published in Palermo in 1558 in Latin.

At Rome, he became friends with the humanist scholar Paolo Giovio, who encouraged him to write a history of Sicily.

Returning to Palermo, Fazello undertook to teach philosophy and at the same time kept up his religious exercises.

He so devoted himself to his studies that eventually he gave up all but one meal a day and reduced the number of hours he slept each night.