William Alvan Faul (April 21, 1940 – February 21, 2002) was an American Major League Baseball player, a right-handed pitcher for the Detroit Tigers, Chicago Cubs and San Francisco Giants (1962–66; 1970).

Assigned to the Knoxville Smokies of the Sally League, he won six of eight decisions and posted a 2.10 earned run average.

Faul spent all but one game of the 1964 campaign in Triple-A, where he compiled an outstanding win–loss record (11–1) but a high earned run average (4.05) for the Syracuse Chiefs.

The 1965 Cubs tied a major league record by turning three triple plays, and Faul was the pitcher on each occasion.

He began 1966 working out of the bullpen for the Cubs' new manager, Leo Durocher, but got a chance to start on May 1 against the Philadelphia Phillies at Wrigley Field.

After spending 31⁄2 years in the minors, he surfaced in the majors again as a member of the Giants' 1970 bullpen, appearing in seven May games and registering one save.