L'œuvre is the fourteenth novel in the Rougon-Macquart series by Émile Zola. It was first serialized in the periodical Gil Blas beginning in December 1885 before being published in novel form by Charpentier in 1886.

The title, translated literally as "The Work" (as in work of art), is often rendered in English as The Masterpiece or His Masterpiece. It refers to the struggles of the protagonist Claude Lantier to paint a great work reflecting his talent and genius.

L'œuvre is a fictional account of Zola's friendship with Paul Cézanne and a fairly accurate portrayal of the Parisian art world in the mid 19th century. Zola and Cézanne grew up together in Aix-en-Provence, the model for Zola's Plassans, where Claude Lantier is born and receives his education. Like Cézanne, Claude Lantier is a revolutionary artist whose work is misunderstood by an art-going public hidebound by traditional subjects, techniques and representations. Many of the characteristics ascribed to Claude Lantier are a compound taken from the lives of several impressionist painters including Claude Monet, Édouard Manet, as well as Paul Cézanne. Zola's self-portrait can be seen in the character of the novelist Pierre Sandoz.