William Smythe

William Smythe may refer to:


 * W. E. Smythe (William Ellsworth Smythe, 1861–1922), journalist, writer and founder of the Little Landers movement
 * William Smythe (physicist) (1893–1988), American physicist and mentor of six Nobel Prize laureates
 * William James Smythe (1816–1887), general and colonel-commandant of the Royal Artillery
 * William Smythe (academic), Oxford college head
 * Harry Smythe (William Henry Smythe, 1904–1980), pitcher in Major League Baseball
 * William Smythe of the Smythe baronets
 * William Smythe (geophysicist) and namesake of Smythe Shoulder