The announcement was made Thursday at Tournament House in Pasadena. The 85-year-old Scully will ride in the parade, themed "Dreams Come True," and toss the coin at the start of the 100th Rose Bowl Game.
Tournament of Roses President R. Scott Jenkins said he picked Scully because of his humility, integrity and his accomplishments as the play-by-play announcer for the Los Angeles Dodgers.
"Vin Scully is incredibly accomplished and yet still so down to Earth," Jenkins said in a statement. "His own life is one in which many dreams have come true and even more importantly, he has been at the microphone describing for listeners everywhere the dreams of others coming true."
Scully announced last month that he would be returning in 2014 for a record 65th season announcing games for the Dodgers. He has been doing play-by-play for the Dodgers since 1950, when they were based in Brooklyn.
"I am deeply humbled and greatly honored to be the grand marshal of the 125th Rose Parade," Scully said in a statement. "I look forward to sharing this wonderful moment with my wife, Sandi, and the millions who will be watching."