William Domingos Barrett (born March 9, 1981) is a former professional baseball pitcher. He was selected by the Minnesota Twins in the 7th round (212th overall) of the 2002 Major League Baseball Draft. He bats and throws left-handed. Barrett signed with the Tokyo Yakult Swallows of Japan's Central League for the 2009 season. He last played for the Southern Maryland Blue Crabs of the Atlantic League of Professional Baseball in 2012.