The 2026 Norwegian First Division (referred to as OBOS-ligaen for sponsorship reasons) will be the Norwegian second-tier men's professional football league season. The season will start on April 6th and is scheduled to end on November 8th, not including play-off matches.
The following teams have changed division since the 2025 season:
Promoted from Second Division
Relegated from Eliteserien
Promoted to Eliteserien
Relegated to Second Division
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The teams from third to sixth place will take part in the promotion play-offs; these are single leg knockout matches. In the first round, the fifth-placed team will play at home against the sixth-placed team. The winner of the first round will meet the fourth-placed team on away ground in the second round. The winner of the second round will meet the third-placed team on away ground. The winner of the third round will face the 14th-placed team in the Eliteserien over two legs in the Eliteserien play-offs for a spot in the 2027 Eliteserien.
The 14th-placed team will take part in a two-legged play-off against the winners of the Second Division play-offs, to decide who will play in the 2027 First Division.