Ernest DiGregorio (born January 15, 1951), also known as "Ernie D.", is an American former National Basketball Association player. He was named NBA Rookie of the Year in the 1973–74 season and holds the NBA rookie record for assists in a single game with 25. Due to a severe knee injury suffered early in DiGregorio's professional career, he played only five NBA seasons.
A 1973 NCAA All-American at Providence, DiGregorio was inducted into the College Basketball Hall of Fame in 2019.
DiGregorio played on the 1968 Rhode Island (Class B) champions at North Providence High School. He and Marvin Barnes led Coach Dave Gavitt's Providence team to a Final Four appearance in the 1973 NCAA Tournament in DiGregorio's senior season, where they eventually lost to Memphis State, but only after Barnes sustained a knee injury that forced an early exit. After playing for the Providence College Friars, DiGregorio played on a college all-star team, and along with Bill Walton, led the U.S. in defeating a Soviet team in an exhibition game, which helped heal the still-open wound of the United States' loss in the 1972 Summer Olympic finals. Ernie "D" was then drafted by the Kentucky Colonels of the American Basketball Association but opted instead for the NBA.