Paul Nicholas "Lefty" Masterson (October 16, 1915 – November 27, 1997) was an American Major League Baseball pitcher.

Masterson entered professional baseball in 1937 making his Major League debut with the Phillies on September 15, 1940.

His only decision came on September 23, 1941, when the Phillies hosted the New York Giants at Shibe Park.

[1] Masterson died in Chicago, the city of his birth, on November 27, 1997, aged 82.

This biographical article relating to an American baseball pitcher born in the 1910s is a stub.