Jean-Marie Valentin (French: [ʒɑ̃maʁi valɑ̃tɛ̃]; 17 October 1823 – 8 August 1896) was a French architect and sculptor specialising in religious furnishings such as pulpits, altars and statues.

Born in Bourg-des-Comptes, Ille-et-Vilaine, he died in the 6th arrondissement of Paris at age 72. His father Antoine Louis Valentin (born 1784) was a master carpenter working mostly in ebony. Jean-Marie first worked at his father's workshop.

In 1842, he studied at the École Municipale de Dessin et Sculpture in Rennes (this became the École Régionale des Beaux-Arts in 1881). He was taught sculpture by Jean-Baptiste Barré. In 1845, he received a bursary from the city of Rennes and travelled to Paris where he worked at a studio together with a Rennes sculptor called François Lanno. He then worked at the studio of François Rude. In around 1850 he settled back in Rennes and started to specialise in church furnishings. His works are numerous and can be seen throughout Ille-et-Vilaine.

His first masterpiece was the pulpit erected in the Église Sainte-Croix à Saint-Servan, a suburb of Saint-Malo). This had been promoted and funded by Napoleon III during his visit to Brittany in 1858. During this visit, the church's curate, Monsieur Huchet, had brought the church to the Emperor's attention, highlighting the fact that it lacked furnishings. The Emperor was generous and the pulpit was the result. Jean-Marie was assisted by his brother Antoine, as was often the case, and the pulpit was indeed signed "Valentin Frères, Architectes et sculpteurs". Many years later Valentin completed the memorial to Huchet in the Saint-Malo cathedral.

Perhaps his best-known work was on the Saint-Yves funeral monument in the cathedral at Tréguier. For this work he received a prize in 1888 from the "Salon des Artistes français" where it was shown before installation in the cathedral.

For this church in Ercé-près-Liffré's place de l'Eglise, Valentin created the work "Education de la Vierge" in 1861.

Valentin executed the altar and altarpiece dedicated to saint Gilduin de Chartres and saint Méen in this cathedral in 1873. The wall behind the altar is painted with medallions in quinconce holding the letters "S.G" and "S.M.", these surrounded by a neo-gothic frieze painted by the Rennes artist Lemoine. The altar includes a bronze reliquary by Placide Poussièlgue-Rusand and a small terra cotta figure of a hermit by an unknown artist. Valentin also worked on the Sacré Coeur altar in the cathedral but not the four statues which form part of the altar. Two of these statues, those of saint Peter and saint Paul, are by the sculptor Robert Froc. Another altar in Dol cathedral by Valentin is that dedicated to saint Gilles and saint Roch and it is thought that the statues of Gilles, Roch and saint Thuriau de Dol are possibly the work of Valentin but this is not clear. Also in the cathedral is Valentin's statue of 1872 entitled "l'Education de la Vierge". This was at one time part of the altar and altarpiece dedicated to Sainte-Anne by the sculptor Augerie executed in 1899 but taken down in 1975. In 1876, Valentin also worked on the cathedral's Saint Michel altar and altarpiece. Apart from the statue of Saint Michel, the work also includes a statue of Saint Louis and Saint Sebastian.

For this parish church in Hédé, Valentin executed a statue of saint Joseph in 1866.