Julie or the New Heloise, originally entitled Lettres de Deux Amans, Habitans d'une petite Ville au pied des Alpes, is an epistolary novel by Jean-Jacques Rousseau, published in 1761 by Marc-Michel Rey in Amsterdam. The novel's subtitle points to the history of Héloïse d'Argenteuil and Peter Abélard, a medieval story of passion and Christian renunciation.

An epistolary novel is a novel written as a series of letters between the fictional characters of a narrative. The term is often extended to cover novels that intersperse documents of other kinds with the letters, most commonly diary entries and newspaper clippings, and sometimes considered to include novels composed of documents even if they do not include letters at all. More recently, epistolaries may include electronic documents such as recordings and radio, blog posts, and e-mails. The word epistolary is derived from Latin from the Greek word epistolē, meaning a letter (see epistle). This type of fiction is also sometimes known by the German term Briefroman or more generally as epistolary fiction.