2021 Norwegian Second Division

The 2021 Norwegian Second Division (referred to as PostNord-ligaen for sponsorship reasons) was a Norwegian football third-tier league season. The league consisted of 28 teams divided into 2 groups of 14 teams.

The league was played as a double round-robin tournament, where all teams played 26 matches. The season started on 19 June 2021 and concluded on 14 November 2021.

Kongsvinger earned promotion from group 1 on 23 October 2021, three rounds before the end of the season. Skeid secured promotion from group 2 on 6 November 2021, following a 12–0 win against Rosenborg 2.

Team changes
The following teams changed division since the 2020 season.

To 2. divisjon

 * Relegated from 1. divisjon
 * Kongsvinger
 * Øygarden

From 2. divisjon

 * Promoted to 1. divisjon
 * Bryne
 * Fredrikstad

Teams
The following 14 clubs compete in group 1:

Teams
The following 14 clubs compete in group 2:

Promotion play-offs
The teams who finished in second place in their respective group qualified for the promotion play-offs, where they faced each other over two legs. The winner went on to play against the 14th-placed team in the First Division for a place in the First Division next season.

Hødd won 4–3 on aggregate.