The Boncompagni is an Italian noble family from Assisi.
The family is documented for the first time in 1133, when one Rodolfo Boncompagni, descendant of Saxon nobles, was appointed by Lothair II as lord of Assisi. In the early 14th century the family moved from Umbria to Bologna, where they gradually increased their wealth and influence.
In 1572 Ugo Boncompagni, a professor of law in the University of Bologna and a Catholic cardinal, became pope as Gregory XIII. For his son Giacomo Boncompagni, he acquired from Francesco Maria II della Rovere the Duchy of Sora, which thenceforth became a family possession. The family also included five other cardinals in the 17th and 18th centuries.