The terms of the deal weren't revealed, but the Milwaukee Journal Sentinel reported it was for three years at $24 million.
Mayo, 25, played the Dallas Mavericks last season, averaging 15.3 points and 4.4 assists percent while shooting 40.7 percent from 3-point range over 82 games.
He came to Dallas from the Memphis Grizzlies, for whom he played in the each of previous four seasons.
Over 383 career games, the former third-overall draft pick has compiled totals of 15.2 points, 3.4 rebounds and 3.1 assists per game.
Swim Week Miami Beach 2014 [PHOTOS]