Firlej is the surname of 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. He was nicknamed Firlej, and the name became his family name. From 15th to 17th century, the Firlej family was a powerful magnate family in the Lesser Poland (Małopolska) region. A branch of the family became a vocal supporter of Protestantism in Poland.
The family went extinct in 18th century.