William Hendrick Foster[2] (June 12, 1904 – September 16, 1978) was an American left-handed pitcher in baseball's Negro leagues in the 1920s and 1930s.

[5] Foster played for the Memphis Red Sox in 1923 and 1924, the Chicago American Giants from 1925 to 1930—and again from 1932 to 1935 and in 1937—the Homestead Grays and Kansas City Monarchs in 1931, and the Pittsburgh Crawfords in 1936.

[7] In 1926, Foster won 23 games in a row and 26 overall, but his most amazing performance came the last day of the playoffs to determine the Negro National League title.

Foster finished the 1931 campaign with J. L. Wilkinson's Kansas City Monarchs where on October 4, 1931 he blew his fastball past a major league all-star team composed of such legendary men as Babe Herman, Joe Kuhel and both Waner brothers, Lloyd and Paul.

Umpire Jocko Conlan said Foster had "the same perfect delivery of Herb Pennock, but was faster by far, with a sharp curve, and had what all great pitchers have – control."

Negro league player and manager Dave Malarcher favorably compared him to Negro league legend Satchel Paige, saying, "Bill Foster was my star pitcher, the greatest pitcher of our time, not even barring Satchel.

"[14] After retiring from professional baseball in 1936, Foster moved to Tarboro, North Carolina, where his childhood sweetheart Thelma Quigless lived.

From 1960 to 1977, Foster was a dean and the baseball coach at his alma mater, Alcorn Agricultural and Mechanical College.