William Howard Annan (December 14, 1850 – unknown) was a professional baseball umpire.
Annan umpired one National Association game in 1873, between the Brooklyn Atlantics and the Boston Red Stockings (today's Atlanta Braves).Annan was also a minor league shortstop, played for Harvard University, and earned a law degree there.
He was a lawyer in Baltimore from 1880 to 1885, studied at the University of Edinburgh, then moved to London and later New York City.