Mary Stevenson Cassatt ( /kəˈsæt/; May 22, 1844 – June 14, 1926) was an American painter and printmaker. She lived much of her adult life in France, where she first befriended Edgar Degas and later exhibited among the Impressionists. Cassatt often created images of the social and private lives of women, with particular emphasis on the intimate bonds between mothers and children.

She was described by Gustave Geffroy in 1894 as one of "les trois grandes dames" of Impressionism alongside Marie Bracquemond and Berthe Morisot.

Cassatt was born in Allegheny City, Pennsylvania, which is now part of Pittsburgh. She was born into an upper-middle-class family: her father, Robert Simpson Cassat (later Cassatt), was a successful stockbroker and land speculator, and her mother, Katherine Kelso Johnston, came from a banking family. Katherine Cassatt, educated and very well read, had a profound influence on her daughter. To that effect, Cassatt's lifelong friend Louisine Havemeyer wrote in her memoirs: "Anyone who had the privilege of knowing Mary Cassatt's mother would know at once that it was from her and her alone that [Mary] inherited her ability." The ancestral name had been Cossart. Cassatt was a distant cousin of artist Robert Henri. Cassatt was one of seven children, of which two died in infancy. Her family moved eastward, first to Lancaster, Pennsylvania, then to the Philadelphia area, where she began schooling at age 6.