Alessandro Achillini (October 20, 1463 - August 12, 1512), Italian philosopher, was born at Bologna.

He was celebrated as a lecturer both in medicine and in philosophy at Bologna and Padua, and was styled the second Aristotle. His philosophical works were printed in one volume folio, at Venice, in 1508, and reprinted with considerable additions in 1545, 1551 and 1568.

He was also distinguished as an anatomist, among his writings being Corpores humani Anatomia (Venice, 1516-1524), and Anatomicae Annotationes (Bologna, 1520). He died at Bologna on the 2nd of August 1512.

His brother, Giovanni Filoteo Achillini (1466-1533), was the author of Il Viridario and other writings, verse and prose, and his grand-nephew, Claudio Achillini (1574-1640), was a lawyer who achieved some notoriety as a versifier of the school of the Secentisti .