Kenneth Alphonse Heintzelman (October 14, 1915 – August 14, 2000) was an American professional baseball pitcher who played all or part of 13 seasons in Major League Baseball (MLB) for the Pittsburgh Pirates (1937–42 and 1946–47) and Philadelphia Phillies (1947–52). He threw left-handed, batted right-handed, and was listed as 5 feet 11 inches (1.80 m) tall and 185 pounds (84 kg). His son, Tom, was an MLB infielder during the 1970s.