| Competition: | 1. Liga |
| Season: | 1965–66 |
| Winners: | 1. Liga champions: FC Wettingen Group West: Etoile Carouge Group Cenral: FC Langenthal Group South and East: FC Wettingen |
| Promoted: | FC Wettingen FC Xamax |
| Relegated: | Group West: FC Meyrin FC Montreux-Sports Group Central: FC Trimbach US Bienne-Boujean Group South and East: FC Dietikon FC Oerlikon/Polizei ZH |
| Matches: | 3 times 156 and 1 decider plus 12 play-offs |
| Prevseason: | 1964–65 |
| Nextseason: | 1966–67 |
The 1965–66 1. Liga season was the 34th season of the 1. Liga since its creation in 1931. At this time, the 1. Liga was the third-tier of the Swiss football league system and it was the highest level of total amateur football. At this time, most of the teams in the top two tiers were professional or at least semi-professional.
There were 39 teams competing in the 1. Liga 1965–66 season. They were divided into three regional groups, each group with 13 teams. Within each group, the teams would play a double round-robin to decide their league position. Two points were awarded for a win. The three group winners and the three runners-up then contested a play-off round to decide the two promotion slots. The last two placed teams in each group were relegated to the 2. Liga (fourth tier).
| Club | Based in | Canton | Stadium | Capacity |
|---|---|---|---|---|
| CS Chênois | Thônex | Stade des Trois-Chêne | ||
| Étoile Carouge FC | Carouge | Stade de la Fontenette | ||
| FC Fribourg | Fribourg | Stade Universitaire | ||
| FC Martigny-Sports | Martigny | Stade d'Octodure | ||
| FC Meyrin | Meyrin | Stade des Arbères | ||
| FC Montreux-Sports | Montreux | Stade de Chailly | ||
| FC Forward Morges[1] | Morges | Parc des Sports | ||
| FC Raron[2] | Raron | Sportplatz Rhoneglut | ||
| FC Stade Lausanne | Ouchy, Lausanne | Centre sportif de Vidy | ||
| FC Versoix[3] | Versoix | Centre sportif de la Bécassière | ||
| Vevey Sports | Vevey | Stade de Copet | ||
| Xamax | Neuchâtel | Stade de la Maladière | ||
| Yverdon-Sport FC | Yverdon-les-Bains | Stade Municipal | ||
| Club | Based in | Canton | Stadium | Capacity | |
|---|---|---|---|---|---|
| FC Alle | Alle | Centre Sportif Régional | |||
| FC Bern | Bern | Stadion Neufeld | |||
| US Bienne-Boujean | Biel/Bienne | ||||
| SC Burgdorf[4] | Burgdorf | Stadion Neumatt | |||
| FC Concordia Basel | Basel | Stadion Rankhof | |||
| SR Delémont | Delémont | La Blancherie | |||
| FC Fontainemelon[5] [6] | Neuchâtel | Centre Sportif Fontainemelon | |||
| FC Langenthal[7] | Langenthal | Rankmatte | |||
| FC Minerva Bern | Bern | Spitalacker | |||
| FC Nordstern Basel | Basel | Rankhof | |||
| FC Olten[8] | Olten | Sportanlagen Kleinholz | |||
| FC Trimbach | [9] | Trimbach | Sportanlage Leinfeld | ||
| FC Wohlen | Wohlen | [10] | |||
| Club | Based in | Canton | Stadium | Capacity |
|---|---|---|---|---|
| FC Amriswil[11] | Amriswil | Tellenfeld | ||
| FC Dietikon[12] | Dietikon | Fussballplatz Dornau | ||
| FC Emmenbrücke | Emmen | Stadion Gersag | ||
| FC Küsnacht[13] | Küsnacht | Sportanlage Heslibach | ||
| FC Locarno | Locarno | |||
| FC Oerlikon/Polizei ZH[14] | Oerlikon (Zürich) | Sportanlage Neudorf | ||
| FC Red Star Zürich | Zürich | Allmend Brunau | ||
| FC Rorschach[15] | Rorschach | Sportplatz Kellen | ||
| FC Schaffhausen | Schaffhausen | Stadion Breite | ||
| FC Vaduz | Vaduz | Liechtenstein | Rheinpark Stadion | |
| FC Wettingen | Wettingen | Stadion Altenburg | ||
| FC Widnau[16] | Windnau | Sportanlage Aegeten | ||
| SC Zug | Zug | Herti Allmend Stadion | ||
The decider was played in Frauenfeld. FC Amriswil win and remain in the division. FC Dietikon were relegated to 2. Liga Interregional.
The three group winners played a round-robin against the four teams who had not been in their group. The teams did not play against the team that had been in the same group.
The first games were played on 5 June
The second round was played on 12 June
The third round was played on 19 June
The final round was played on 26 June