Francis Throckmorton was a Catholic conspirator. Although his name is usually attached to the famous plot of 1583, he probably only acted as a 'go-between'. The plan involved an invasion led by the French Duke of Guise and paid for by Philip of Spain, the aims of which were to overthrow Elizabeth and put Mary Queen of Scots on the throne.

Throckmorton was eventually identified by Walsingham's spies in France and arrested. Under torture, he revealed the details of the plot, including links that were made between Mary and agents acting on her behalf in France, but no letters were found to provide evidence of her direct involvement.