Gaston Lavalley (29 November 1834 in Vouilly – 1922) was a French writer, historian and art historian. He was a son of the engineer Louis-Auguste Lavalley-Dupéroux (1800–1885) and brother to Georges-Aimar Lavalley (1830–1882), later director of Caen's Musée des Antiquité and writer on religious buildings in the diocese of Bayeux. Gaston studied law before being made chief curator of the town library in Caen in 1870. Specialising in the history of Normandy, he contributed to many local and national journals and wrote many books, of which the main one is Légendes normandes.