Giovanni Alfonso Borelli (January 28, 1608 - December 31, 1679) was an Italian physiologist and physicist.

Borelli was born at Naples. He was appointed professor of mathematics at Messina in 1649 and at Pisa in 1656. In 1667 he returned to Messina, but in 1674 was obliged to retire to Rome, where he lived under the protection of Christina of Sweden.

Borelli's best-known work is On the Movement of Animals (Rome, 1680-1681), in which he sought to explain the movements of the animal body on mechanical principles; for this he has earned the title of the father of biomechanics.

In a letter, Del movimento della cometa apparsa il mese di decembre 1664, published in 1665 under the pseudonym Pier Maria Mutoli, he was the first to suggest the idea of a parabolic path; and another of his astronomical works was Theorica mediceorum planetarum ex causis physicis deducta (Florence, 1666), in which he considered the influence of attraction on the satellites of Jupiter.

Borelli also wrote:

• Della cagioni delle febbri maligne (Pisa, 1658)
• Euclides Restitutus (Pisa, 1658)
• Apollonii Pergaei Conicorum libri v., vi. et vii. (Florence, 1661)
• De vi percussionis (Bologna, 1667)
• Meteorologia Aetnea (Reggio, 1669)
• De motionibus naturalibus a gravitate pendentibus (Bologna, 1670).