Roger IV (died 24 February 1265), son and successor of Roger-Bernard II the Great, was the eighth count of Foix from 1241 to his death.
Roger IV was a vassal of both the count of Toulouse (for his county of Foix) and the king of France (for his Carcassonne lands), then Louis IX.
The count of Foix was now solely a vassal of the king and Raymond spent the rest of his life (until 1249) trying to retrieve Roger's homage, to no avail.
In February 1245, he gave many freedoms to his subjects and he signed paréages with the abbots of Mas-d'Azil (1246), Boulbonne (1253), and Combelongue (1255).
In 1251, he built the church at Boulbonne, transferred his ancestors' remains there, and defended it against the exactions of numerous enemies.