Gerald VI, (1235–1285), was Viscount Fezensaguet from 1240 to 1285, then Count of Armagnac and Fézensac from 1256 to 1285.

In this war Gerald was supported by his overlord, Count Raymond VII of Toulouse.

During his captivity, his mother, Pincelle d'Albret, presented in his name the county of Fezensaguet as tribute to Alphonse of Poitiers, the successor of Raymond VII, in return for continued support.

In 1256, after the death of the childless Mascarós II Lomagne, Gerald, being her closest relative, inherited the counties of Armagnac and Fezensac.

Following numerous quarrels with the Seneschal of Languedoc, he was captured and imprisoned two years in the castle of Peronne.