| Season: | 1979–80 |
| Competition: | Nationalliga A |
| Winners: | Basel |
| Relegated: | La Chaux-de-Fonds Lugano |
| Continentalcup1: | European Cup |
| Continentalcup1 Qualifiers: | Basel |
| Continentalcup2: | Cup Winners' Cup |
| Continentalcup2 Qualifiers: | Sion |
| Continentalcup3: | UEFA Cup |
| Continentalcup3 Qualifiers: | Grasshopper Club Servette |
| League Topscorer: | Claudio Sulser (GC) 25 goals |
| Prevseason: | 1978–79 |
| Nextseason: | 1980–81 |
| Season: | 1979–80 |
| Competition: | Nationalliga B |
| Winners: | Bellinzona |
| Promoted: | Bellinzona Nordstern |
| Relegated: | FC Raron FC Baden |
| League Topscorer: | Roger Ries (Nordstern) 17 goals |
| Prevseason: | 1978–79 |
| Nextseason: | 1980–81 |
The following is the summary of the Swiss National League in the 1979–80 football season, both Nationalliga A and Nationalliga B. This was the 83rd season of top-tier and the 82nd season of second-tier football in Switzerland.
The Swiss Football Association (ASF/SFV) had 28 members at this time. The clubs were divided into two tiers, now both tiers with of 14 teams each, the top tier Nationalliga A (NLA) had been increased by two and the second tier Nationalliga B (NLB) decreased by two. The format in both divisions was that the teams played a double round-robin to decide their table positions. Each club playing every other club twice (home and away) for a total of 26 rounds. Two points were awarded for a win and one point was awarded for a draw. The top placed six teams then played a championship stage. For all others teams the season was complete. In the championship group the teams played another double round-robin and each team took half of the points gained in the first stage, rounded up to complete units, as bonus with them.
The Swiss champions would qualify for the 1980–81 European Cup, the runners-up and third placed team would qualify for the 1980–81 UEFA Cup. The last two teams of the NLA were relegated to the second-tier. The top two teams in the NLB were promoted to top-level. The bottom two teams were relegated to the 1980–81 1. Liga.
The first round of the NLA was played on 11 August 1979. There was a winter break between 2 December and 2 March 1980. The season was completed on 20 May and the championship group on 30 June 1980.