William Willet (November 1, 1869 – March 29, 1921) was an American portrait painter, muralist, stained glass designer, studio owner and writer.

He assisted John La Farge between 1885 and 1887 during which time he served as art director and painted faces on murals.

[4] As a member of what Charles J. Connick termed the "Early School" of stained glass artists, Willet, and fellow craftsmen Otto Heinigke and Harry E. Goodhue, are credited with renewing America's interest in traditional medieval materials, techniques, and aesthetic.

The first medallion window, designed and executed for First Presbyterian Church of Pittsburgh was composed of antique stained glass in the medieval manner.

[6] Before it was hidden from view, however, it caught the attention of Neo-Gothic architect Ralph Adams Cram who would later serve as a patron for many of the Willet's works.

[7] In 1910 Willet won the commission for the Great Sanctuary Window in the Cadet Chapel at the United States Military Academy in West Point, New York.