John Ray Sinnock (July 8, 1888 – May 14, 1947) was the eighth Chief Engraver of the United States Mint from 1925 to 1947.

Sinnock was born July 8, 1888, in Raton, New Mexico, and was educated at the Pennsylvania Museum School of Industrial Art.

His longtime confidante was Margaret Campbell, who inherited much of his artwork as well as his personal collection of materials related to the development of the Roosevelt Dime.

[2] Upon the initial minting of the Roosevelt dime in 1946, an urban legend arose in the United States that the letters "JS" actually stood not for John Sinnock, but for Joseph Stalin.

Sinnock said that he also consulted photographs of FDR and had the advice and criticism of two prominent sculptors who specialize in work in relief.