In one of the biggest debates in the four years of the College Football Playoff, the selection committee on Sunday picked Alabama over Ohio State as the last team into the final four.
Defending national champion Clemson (12-1) is the top seed and will play the fourth-seeded Crimson Tide for the third consecutive year in the postseason.
Alabama (11-1) beat the Tigers for the 2015 national title, with Clemson turning the tables last season.
No. 2 Oklahoma (12-1) will play No. 3 Georgia in the other semifinal, in the Rose Bowl on Jan. 1.
Clemson-Alabama will take place the same day in the Sugar Bowl.
For the first time, two teams from the same conference -- Alabama and Georgia from the SEC -- are among the final four teams.
For the second consecutive season, the Big Ten champion is left out.
Last season, the committee bypassed Big Ten champ Penn State to take Ohio State. This year, the committee bypassed the Buckeyes to take Alabama, which, like Ohio State in 2016, failed to win its own conference division.
Ohio State (11-2) finished fifth in the selection committee rankings.
Wisconsin, which lost to the Buckeyes in the Big Ten Championship Game on Saturday to suffer its first loss, dropped from No. 4 to No. 6.
Alabama is the only team to appear in all four years of the playoffs. Clemson is making its third appearance. This is Oklahoma's second appearance, and the first time for Georgia.
The national title game will be held Jan. 8 in Atlanta.