William Daniel MacLeod (May 13, 1942 – December 12, 2018) was an American relief pitcher in Major League Baseball who played briefly for the Boston Red Sox during the 1962 season.

After signing with the Red Sox, he marked his 1961 professional baseball debut by winning 15 of 23 decisions at Winston-Salem of the Class B Carolina League.

When rosters expanded late that season, he was recalled by the Red Sox for his first (and, ultimately, his only) MLB opportunity, appearing in relief in two road games.

On September 13, against Detroit at Tiger Stadium, he relieved the starting pitcher, fellow rookie Pete Smith, in the fourth inning with Boston already trailing 8–0.

MacLeod retired the only man he faced, veteran centerfielder Bill Bruton, on a ground ball to shortstop, then exited the game for a pinch hitter.