Scully, who will be 86 when the parade is held for the 125th time on New Year's Day, recently announced he would return to the Los Angeles Dodgers broadcast booth for a 65th season.
"I am deeply humbled and greatly honored to be the grand marshal of the 125th Rose Parade," Scully said. "I look forward to sharing this wonderful moment with my wife, Sandi, and the millions who will be watching."
Scully was inducted into the National Baseball Hall of Fame in 1982. He has broadcast 25 World Series.