| Competition: | Norwegian First Division |
| Season: | 2021 |
| Dates: | 15 May – 27 November |
| Winners: | HamKam |
| Promoted: | HamKam Aalesund Jerv |
| Relegated: | Ull/Kisa Strømmen |
| Matches: | 240 |
| Total Goals: | 765 |
| League Topscorer: | Oscar Aga (24 goals) |
| Biggest Home Win: | 6–2 (1 match) 5–1 (4 matches) 4–0 (3 matches) |
| Biggest Away Win: | |
| Highest Scoring: | |
| Longest Wins: | 5 matches Aalesund HamKam Jerv[1] |
| Longest Unbeaten: | 23 matches Aalesund |
| Longest Winless: | 17 matches Strømmen |
| Longest Losses: | 7 matches Ull/Kisa |
| Prevseason: | 2020 |
| Nextseason: | 2022 |
| Updated: | 27 November 2021 |
The 2021 Norwegian First Division (referred to as OBOS-ligaen for sponsorship reasons) is a Norwegian second-tier football league season.
The league started on 15 May 2021, and ended on 27 November 2021.[2]
HamKam earned promotion to Eliteserien on 6 November 2021, after a 1–0 win against Stjørdals-Blink.[3] Aalesund secured their promotion in the penultimate round.
In the 2020 1. divisjon, Tromsø and Lillestrøm were promoted to the 2021 Eliteserien, while Kongsvinger and Øygarden were relegated to the 2021 2. divisjon.
Start and Aalesund were relegated from the 2020 Eliteserien, while Fredrikstad and Bryne were promoted from the 2020 2. divisjon.
| Team | Location | Arena | Capacity[4] | Manager | |
|---|---|---|---|---|---|
| Aalesund | Ålesund | Color Line Stadion | 10,778 |  Lars Arne Nilsen | |
| Bryne | Bryne | Bryne Stadion | 4,000 | Jan Halvor Halvorsen | |
| Fredrikstad | Fredrikstad | Fredrikstad Stadion | 12,500 | Bjørn Johansen | |
| Grorud | Oslo | Grorud Arctic Match | 1,700 | Johan Gjønnes Nilsen | |
| HamKam | Hamar | Briskeby Arena | 7,800 | Kjetil Rekdal | |
| Jerv | Grimstad | Levermyr Stadion | 3,300 | Arne Sandstø | |
| KFUM Oslo | Oslo | KFUM Arena | 2,000 | Jørgen Isnes | |
| Ranheim | Trondheim | Extra Arena | 3,000 | Hugo Pereira | |
| Raufoss | Raufoss | Nammo Stadion | 1,800 | Christian Johnsen | |
| Sandnes Ulf | Sandnes | Øster Hus Arena | 6,043 | Bjarne Berntsen | |
| Sogndal | Sogndal | Fosshaugane Campus | 5,622 | Eirik Bakke | |
| Start | Kristiansand | Sør Arena | 14,448 | Sindre Tjelmeland | |
| Stjørdals-Blink | Stjørdalshalsen | M.U.S Stadion | 2,000 | Tom Dent | |
| Strømmen | Strømmen | Strømmen Stadion | 2,000 | Ole Martin Nesselquist | |
| Ull/Kisa | Jessheim | Jessheim Stadion | 4,500 | Steffen Landro | |
| Åsane | Bergen | Åsane Arena | 3,300 | Morten Røssland |
| Team | Outgoing manager | Manner of departure | Date of vacancy | Table | Incoming manager | Date of appointment | Table | |
|---|---|---|---|---|---|---|---|---|
| Stjørdals-Blink | Roar Vikvang | Appointed head of Rosenborg's academy | 31 December 2020[5] | Pre-season | Tom Dent | 1 January 2021[6] | Pre-season | |
| Ull/Kisa | Trond Fredriksen | Mutual consent | 11 January 2021[7] | Sindre Tjelmeland | 12 January 2021[8] | |||
| Grorud | Eirik Kjønø | Signed by Stabæk as assistant | 4 February 2021[9] | Aksel Bergo | 1 March 2021[10] | |||
| Start |  Jóhannes Harðarson | Sacked | 14 June 2021[11] | 7th | Sindre Tjelmeland | 19 June 2021[12] | 12th | |
| Ull/Kisa | Sindre Tjelmeland | Signed by Start | 19 June 2021 | 11th | Arild Sundgot | 1 July 2021[13] | 11th | |
| Ranheim | Svein Maalen | Mutual consent | 22 June 2021[14] | 15th | Hugo Pereira | 7 July 2021[15] | 15th | |
| Sandnes Ulf | Steffen Landro | Mutual consent | 14 July 2021[16] | 16th | Bjarne Berntsen | 12 August 2021[17] | 14th | |
| Grorud | Aksel Bergo | Mutual consent | 27 August 2021[18] | 16th | Johan Gjønnes Nilsen (interim) | 27 August 2021 | 16th | |
| Ull/Kisa | Arild Sundgot | Sacked | 3 October 2021[19] | 14th | Steffen Landro | 5 October 2021[20] | 14th |
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 advance to play the 14th-placed team in the Eliteserien on neutral ground in the Eliteserien play-offs for a spot in the top-flight next season.[21]
The 14th-placed team, Stjørdals-Blink, took part in a two-legged play-off against the winners of the Second Division play-offs, Hødd, to decide who would play in the First Division next season.[22]
Stjørdals-Blink won 5–3 on aggregate.
| Rank | Player | Club | Goals[23] |
|---|---|---|---|
| 1 | Oscar Aga | Grorud | 24 |
| 2 | Sigurd Hauso Haugen | Aalesund | 21 |
| 3 | Elias Hoff Melkersen | Ranheim | 17 |
| 4 | Eman Markovic | Start | 16 |
| 5 | Jonas Enkerud | HamKam | 14 |
| 6 | Kristian Eriksen | HamKam | 13 |
| Erlend Hustad | Sandnes Ulf | ||
 Taofeek Ismaheel | Fredrikstad | ||
| 9 | Joacim Holtan | Bryne | 11 |
| Alagie Sanyang | KFUM Oslo | ||
| Nicolay Solberg | Fredrikstad |