This will be the third consecutive one-year extension for Lewis.
When he was hired in 2003, Lewis took over a franchise that hadn't had a winning season in 12 years. Lewis has guided the Bengals to the playoffs seven times -- including each of the past five years -- but he has not won a postseason game.
With a 112-101-2 record, Lewis is the Bengals' all-time leader in coaching wins.
Lewis is the NFL's second-longest tenured head coach behind New England's Bill Belichick.