The 2023 Norwegian First Division (referred to as OBOS-ligaen for sponsorship reasons) is a Norwegian second-tier football league season.
The season started on 10 April 2023 and ended on 12 November 2023, not including play-off matches.
In the 2022 Norwegian First Division, Brann and Stabæk were promoted to the 2023 Eliteserien, while Grorud and Stjørdals-Blink were relegated to the 2023 Norwegian Second Division.
Jerv and Kristiansund were relegated from the 2022 Eliteserien, while Moss and Hødd were promoted from the 2022 Norwegian 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 top-flight next season.
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 First Division next season.