Giacomo Antonio Fancelli (1619–1671) was an Italian sculptor in stone and stucco of the Baroque era.
Fancelli was born in Rome. He was the brother of Cosimo Fancelli and a pupil of Bernini. Notable among his works are Nile (hiding his face, since the River Nile's source had not yet been discovered at that date) on Bernini's Fontana dei Quattro Fiumi (completed in 1651) and St Francis (c.1647) in the church of San Bernardo alle Terme on the Quirinal in Rome.