Charles Wardell Stiles (May 15, 1867 – January 24, 1941) was an American parasitologist born in Spring Valley, New York. He was notable for working on a campaign against hookworm infestation in the American South, where it had been found to cause high rates of anemia, a debilitating disease.
He studied science at Wesleyan University in Connecticut (1885–86), Collège de France (1886–87), the University of Berlin (1887–89) and the University of Leipzig (1889–90). In 1891, he continued his education at the zoological station in Trieste and at the Institut Pasteur in Paris. He obtained his doctorate in Leipzig under the direction of parasitologist Rudolf Leuckart (1822–1898).
He taught classes in medical zoology at Johns Hopkins School of Medicine and at Georgetown University. He also worked as a zoologist for the U.S. government at the Bureau of Animal Industry in the Department of Agriculture (1891–1902), and was later chief zoologist at the Hygienic Laboratory of the US Public Health and Marine Hospital Service (1902–1931). In 1898, Stiles was deployed to Germany as scientific ambassador on the BAI's behalf to investigate reports of trichinosis in American pork. The investigation concluded that the contemporary standard of microscopic examination pork was insufficient for preventing the disease.