Alethea Hill Platt (December 31, 1860 – May 23, 1932) was an American artist and educator. Her paintings of rural landscapes in France, England, the Adirondacks, and New England were displayed in about 200 exhibitions at venues including the National Academy of Design, Pennsylvania Academy of the Fine Arts, and Louisiana Purchase Exposition. The New York Times found a “quality of serenity, even a kind of nobility” in her work, and American Art News placed her “in the ranks of America’s leading women painters.”