Agnès was the daughter of unknown parents. The date and place of her birth have not been found.
Her husband was Guilhelm VIII de Montpellier. They were married, but the date and place have not been found. Their five known children were Guillaume IX (1202-1204), Tomás (?-?), Raimundo (?-?), Bernat I Guilhelm (?-?) and Inès (?-?).
| Association | Relationship |
|---|---|
| Sancha de Castilla y de Polonia (infanta de Castilla) | tante |