Katherine Milhous (1894–1977) was an American artist, illustrator, and writer. She is known best as the author and illustrator of The Egg Tree, which won the 1951 Caldecott Medal for U.S. picture book illustration. Born into a Quaker family active in the printing industry in Philadelphia, Milhous is also known for her graphic designs for the Works Progress Administration (WPA). Her work has been exhibited at the 1939 New York World's Fair and at the Pennsylvania Academy of the Fine Arts.