Leonardo Agostini (1593-1669) was an Italian antiquary of the 17th century, born at Siena.

After being employed for some time to collect works of art for the Barberini Palace, he was appointed by Pope Alexander VII superintendent of antiquities in the Roman states. He issued a new edition of Paruta's Sicilian Medals, with engravings of 400 additional specimens; and in conjunction with Giovanni Bellori (1615-1696) he also published a work on antique sculptured gems, which was translated into Latin by Jakob Gronovius in Amsterdam, 1685.