Roberto Ridolfi (or di Ridolfo) (18 November 1531 – 18 February 1612) was an Italian and Florentine nobleman and conspirator.
As a banker he had business connections with England, and about 1555 he settled in London, where he soon became a person of some importance, consorting with William Cecil and other prominent men.
In Trinity term 1564 he was recorded as "Robertus Ridolphy, of London, merchant stranger" in a case in Common Pleas.
[1] During the early years of Elizabeth's reign he began to take a more active part in politics, associating with the discontented Roman Catholics in England and communicating with their friends abroad.
However, his messenger to Lesley, Charles Baillie (1542–1625), was seized at Dover and revealed the existence of the plot under torture.