The vestibule is rectangular, with a barrel-vaulted ceiling, decorated with reliefs. The ceiling has octagonal and quadrangular recesses, each with a floral motif or rosette in the centre. Every rosette is different, and in the bottom row they are replaced by the grimacing heads of satyrs and lions. The recesses are directly inspired by Antiquity, and were common in early sixteenth-century Roman architecture.

When the villa was being restored, a painted Borghese coat of arms was found on the main wall of the vestibule above the salone door, referring to a visit by Pope Paul V, a member of the family, in 1608. Below the painting, Latin text on a marble plaque records the fact that two centuries later, in 1807, another pope visited the villa: Pius VII “found respite here from the unrest caused by Napoleon.”