William Porter "Spike" Shannon (February 7, 1878 – May 16, 1940) was a professional baseball player. He was an outfielder over parts of five seasons (1904–1908) with the St. Louis Cardinals, New York Giants and Pittsburgh Pirates. He was the National League leader in runs scored in 1907 with New York. For his career, he compiled a .259 batting average, 183 runs batted in, 383 runs scored, and 145 stolen bases.
Shannon was an alumnus of Grove City College. He was born in Pittsburgh, Pennsylvania, and later died in Minneapolis, Minnesota at the age of 62.
