Auditions kick off at Boston's Emerson College Paramount Theatre on May 5 before travelling to SIR Studios, New York (May 7) and SIR Studios, Nashville (May 14).
They continue at Superior Street, Chicago (May 21), before concluding at Centre Staging, Los Angeles (June 4).
The winner of the group a cappella competition, which is chosen through viewer votes, will scoop a cash prize and a recording contract with Sony Music.
The second season of the show, which was won by Committed, averaged more than nine million viewers during its run on NBC at the end of last year. The first season was won by Nota.
The Sing-Off is hosted by Nick Lachey, and featured Nicole Scherzinger, Shawn Stockman and Ben Folds as celebrity judges in the first two seasons.