Auguste Joseph Alphonse Gratry (usually known as Joseph Gratry) (10 March 1805 − 6 February 1872) was a French author and theologian.
Gratry was born at Lille and educated at the École Polytechnique of Paris. After a period of mental struggle which he has described in Souvenirs de ma jeunesse, he was ordained priest in Strasbourg 1832. After a stay at Strasbourg as professor of the Petit Séminaire, he was appointed director of the Collège Stanislas in Paris in 1842 and, in 1847, chaplain of the École Normale Supérieure. He was awarded the Order of the Legion of Honor in 1845.
In 1852 he and Abbé Pierre Pététot revived Bérulle's Congregation of the Oratory. Gratry was a brilliant academic, holding doctorates in both the humanities and theology. He envisioned communities which could be schools of theological exploration, working with the scientific focus of modern society.
He became vicar-general for the bishop of Orleans in 1861, professor of moral theology at the Sorbonne in 1863, and, on the death of Barante, a member of the Académie française in 1867, where he occupied the seat formerly held by Voltaire.
Together with Abbé Philippe Pététot, pastor of Saint Roch, and Hyacinthe de Valroger, Joseph Gratry reconstituted the French Oratory, a society of priests mainly dedicated to education. Gratry was one of the principal opponents of the definition of the dogma of papal infallibility, but in this matter he submitted to the declarations of the First Vatican Council.