Firlej (plural: Firlejowie) was a Polish szlachta (nobility) family.
According to Kasper Niesiecki, Ostafi of Lewart coat of arms came from Franconia, Germany, to Poland, in 1317, to serve Polish king Władysław Łokietek.
Although most of Jan's sons converted to Catholicism as early as the 1670s, one branch of the family persisted in Calvinism until the mid-17th century, when this one died out.
Over time, the Firlej family declined severely, the richest lines had no male descendants, and the poorer lines grew so large that they fell into the ranks of the middle and poor nobility.
The history of the Firlej family is not fully known or documented.