William Matthew Prior (May 16, 1806 – January 21, 1873) was an American folk artist known for his portraits, particularly of families and children.

[1] In 1840, Prior moved to East Boston, Massachusetts, from his native Bath with his in-laws, notably fellow painter Sturtevant J. Hamblin, to invigorate his career as an artist.

[2] The paintings of Prior and Hamblin, when unsigned, are so similar in style as to be indistinguishable, and are commonly attributed to the "Prior-Hamblin School".

[6] Prior wrote two books about Miller's teachings, The King's Vesture (1862) and The Empyrean Canopy (1868).

Prior is the subject of an exhibition, Artist and Visionary: William Matthew Prior Revealed, shown at the Fenimore Art Museum, Cooperstown, New York (May 26 – December 31, 2012) and subsequently at the American Folk Art Museum in New York City (January 24 – May 26, 2013).