Gaston V (died 1170, before 30 April) was the Viscount of Béarn, Gabardan, and Brulhois from 1153 to his death.
When his father died in 1153, he inherited his title under the regency of his grandmother Guiscarda.
When Guiscarda died in 1154, the Bearnese assembly put him under the tutelage of Raymond Berengar IV of Barcelona and did homage to the Catalan at Canfranc.
It had long ceased to recognize the suzerainty of the Duchy of Aquitaine and had interacted with the King of Aragon as an equal.
After attaining his majority, Gaston married Sancha, daughter of García Ramírez of Navarre, in 1165.