The Twenty20 competition will be cut by 17 matches, featuring 40 home-and-away matches plus four finals from the next edition.
The changes come 12 months in advance of a seven-year broadcast deal agreed between Cricket Australia and media partners Seven Network and Foxtel.
Cricket Australia's general manager of Big Bash Leagues, Alistair Dobson, said a shorter BBL would allow the league "greater flexibility" to deliver the "best possible fixture for clubs and fans".
The Women's Big Bash will remain unchanged from its 59-game season.