Madame de Mauves is a novella by Henry James, originally published in The Galaxy magazine in 1874. The story centers on the troubled marriage of a scrupulous American wife and a far from scrupulous French husband, and is told mostly from the point of view of a male friend of the wife. The tale reflects the intense interest James took in the "international theme," especially early in his career. One of the longest fictions he had yet attempted, the smoothly narrated story shows that James was rapidly maturing in style and technique.

A wealthy American man named Longmore is introduced to his countrywoman Euphemia de Mauves, wife of the Comte Richard de Mauves. Longmore and Madame de Mauves become friends, and he visits her frequently in Paris. Superficially, Madam de Mauves leads a happy life with a wealthy and "irreproachably polite" husband, but Longmore soon becomes convinced that she harbours a deep sadness. It gradually becomes clear that the Comte is an unscrupulous and dissipated man who married his wife for her money alone. As a youth, Madame de Mauves had been naive and idealistic, believing that the Comte de Mauves' title guaranteed a fine character. The Comte, however, proved to have little regard for his wife, and had embarked on a series of extramarital affairs. Even his politeness "was hardly more than a form of luxurious egotism, like his fondness for cambric handkerchiefs.... In after years he was terribly polite to his wife." Madame de Mauves' faith in her ideals is destroyed, but she responds with stoic resignation.

Longmore falls in love with Madame de Mauves, but, understanding that he cannot be her lover, and believing that she desperately needs a friend, he tries to sublimate his love into friendship. This attitude is reinforced by Madame de Mauves, who welcomes his friendship, but is hostile to any sentiment on his part. However both the Comte de Mauves and his sister, the crass widow Madame de Clairin, hint that Longmore should woo Madame de Mauves. The Comte wishes her to take a lover so that he may be free to pursue his own affair.

As tensions mount, the Comte openly breaks with his wife, Madame de Clairin urges Longmore to woo Madame de Mauves, and then she tells Madame de Mauves what she has told Longmore. Longmore agonises over how to proceed; he finds it difficult even to decide to continue his daily visits: "His presence now might be simply a gratuitous cause of suffering; and yet his absence might seem to imply that it was in the power of circumstances to make them ashamed to meet each other's eyes." Eventually he visits Madame de Mauves, who rather cryptically asks him to confirm her very high opinion of him by doing the proper thing: "Don't disappoint me. If you don't understand me now, you will to-morrow, or very soon. When I said just now that I had a very high opinion of you, I meant it very seriously. It was not a vain compliment. I believe that there is no appeal one may make to your generosity which can remain long unanswered. If this were to happen, -if I were to find you selfish where I thought you generous, narrow where I thought you large, ... vulgar where I thought you rare, -I should think worse of human nature. I should suffer, -I should suffer keenly. I should say to myself in the dull days of the future, 'There was one man who might have done so and so; and he, too, failed.' But this shall not be. You have made too good an impression on me not to make the very best. If you wish to please me forever, there's a way."