William Harper’s works are included in the permanent collections of The Metropolitan Museum of Art, New York; the Cooper-Hewitt, Smithsonian Design Museum, New York; Mint Museum of Art, Charlotte, North Carolina; Philadelphia Museum of Art, Pennsylvania; Victoria and Albert Museum, London; Yale University Art Gallery, New Haven, Connecticut; The Vatican Museum, Vatican City, and the Renwick Gallery of the Smithsonian Institution, Washington, DC among others.