Leonardo Agostini (19 September 1593 – August 1676) was an Italian antiquary of the 17th century, born in Boccheggiano, near Grosseto.

His letters to the Barberini family during their period of disgrace and exile (1646–50) have provided art historians with information on the archaeological activity of the time.

Appointed superintendent of antiquities in the Papal States by Pope Alexander VII, he directed excavations in Rome at the Forum and at the thermae near the church of San Lorenzo in Panisperna, where he discovered the "Barberini Hera".

In conjunction with Gian Pietro Bellori (1615–1696) he published Gemme antiche figurate, a work on antique engraved gems, in two volumes (Rome, 1657 and 1669); the first was devoted entirely to Cardinal Francesco's collection, which Agostini had assembled for the papal nephew, and the second to cameos and other discoveries from the auguste ruine della gran Roma (the "august ruins of great Rome").

[4] Agostini was acquainted with all the Roman antiquarians of his day, including Bellori, Cassiano dal Pozzo and Andrea Sacchi; he preserved a volume of Annibale Carracci's ephemeral caricature sketches.