Lorenzo de Tonti (c. 1602 - c. 1684) was a governor of Gaeta, Italy and a Neapolitan banker. He invented the tontine, a form of life insurance.
Around 1650, he and his wife, Isabelle di Lietto, gave birth to their first son, the future explorer Henri de Tonti. Shortly afterwards, Tonti was involved in a revolt against a Spanish viceroy in Naples and had to seek political asylum in France. In Paris, the family gave birth to their second son, Alphonse de Tonty, who later helped establish Detroit, Michigan.
For reasons unknown, Louis XIV had him imprisoned in the Bastille from 1668 to 1675. Around 1684, he died in obscurity of unknown causes.