Julio Julián Castillo Valdez (June 3, 1956 – July 23, 2022) was a Dominican professional baseball infielder and manager. He played in Major League Baseball (MLB) for the Boston Red Sox from 1980 to 1983, and later managed in Minor League Baseball. Listed at 6 feet 2 inches (1.88 m) and 160 pounds (73 kg), he was a switch-hitter and threw right-handed.