Giacomo Filippo Tomasini (17 November 1595 – 13 June 1655) was an Italian Catholic bishop, scholar and historian.

Instructed by Benedetto Benedetti of Legnano, he joined the Venetian order of secular Canons Regular of San Giorgio in Alga when he was fourteen, and received the degree of doctor at Padua in 1619.

[1] He went to Rome, where he was cordially received, especially by Pope Urban VIII, who would have appointed him to a bishopric in the island of Candia.

[1] Tomasini was a close friend and main collaborator of the Greek scholar Leone Allacci.

For the next twenty years, Tomasini acted as Allacci's main contact with antiquarian circles in Padua and Venice.