Spanish satirist and preacher noted for his novel known as Fray Gerundio.

Isla showed intellectual promise early and entered the Jesuit order as a novice in 1719, studying at the University of Salamanca. He was named professor of sacred literature in 1727 and taught this subject in various Spanish schools until 1754, when he retired to Villagarcía to begin work on his masterpiece, Historia del famoso predicador Fray Gerundio de Campazas, alias Zotes (1758; History of the Famous Preacher Friar Gerundio of Campazas, alias Zotes). This work is a brilliant satire on the vain and tastelessly bombastic preaching that predominated in Spanish churches. The book provoked a controversy that ended with its being banned by the Inquisition in 1760. Exiled from Spain with the general expulsion of the Jesuits in 1767, Father Isla went to live temporarily in Corsica and finally in Bologna. Among his other works is a masterly Spanish translation of Gil Blas by the French novelist Lesage.