William Riddle Marshall (September 22, 1875 – December 11, 1959), was a professional baseball player who played catcher for several National League clubs from 1904 to 1909.

[dubious – discuss][citation needed] After his baseball career, Marshall practiced medicine in rural Illinois for 45 years.

Marshall began his professional career relatively late in life, at the age of 27 in 1903, with the Des Moines Undertakers of the Western League, after working as a schoolteacher.

He also played with the Des Moines Undertakers of the Western League and the Milwaukee Brewers and St. Paul Saints of the American Association.

During his baseball career, in both the minor and major leagues, Marshall studied medicine part-time, earning his doctorate in 1909.