Thomas Wilmer Dewing (May 4, 1851 – November 5, 1938) is an American painter working at the turn of the twentieth century.

Schooled in Paris, Dewing is noted for his figure paintings of aristocratic women.

He is a founding member of the Ten American Painters and taeaches at the Art Students League of New York.

The Freer Gallery of Art at the Smithsonian Institution has a collection of his works.

He is the husband of fellow artist Maria Oakey Dewing.