| Competition: | Cypriot First Division |
| Season: | 1990–91 |
| Winners: | Apollon (1st title) |
| Relegated: | APOP APEP |
| Continentalcup1: | European Cup |
| Continentalcup1 Qualifiers: | Apollon (1st round) |
| Continentalcup2: | UEFA Cup |
| Continentalcup2 Qualifiers: | Anorthosis (1st round) |
| Continentalcup3: | Cup Winners' Cup |
| Continentalcup3 Qualifiers: | Omonia (1st round; via Cypriot Cup) |
| League Topscorer: | Suad Beširević Panayiotis Xiourouppas (19 goals)[1] |
| Matches: | 182 |
| Total Goals: | 501 |
| Prevseason: | 1989–90 |
| Nextseason: | 1991–92 |
The 1990–91 Cypriot First Division was the 52nd season of the Cypriot top-level football league. Apollon Limassol won their 1st title.
Fourteen teams participated in the 1990–91 Cypriot First Division. All teams played against each other twice, once at their home and once away. The team with the most points at the end of the season crowned champions. The last two teams were relegated to the 1991–92 Cypriot Second Division. The 12th-placed team faced the 3rd-placed team of the 1990–91 Cypriot Second Division, in a two-legged relegation play-off for one spot in the 1991–92 Cypriot First Division.
The champions ensured their participation in the 1991–92 European Cup and the runners-up in the 1991–92 UEFA Cup.
Teams received two points for a win, one point for a draw and zero points for a loss.
Evagoras Paphos and Ethnikos Achna were relegated from previous season and played in the 1990–91 Cypriot Second Division. They were replaced by the first two teams of the 1989–90 Cypriot Second Division, EPA Larnaca and APEP.
The 12th-placed team Enosis Neon Paralimni faced the 3rd-placed team of the 1990–91 Cypriot Second Division Ethnikos Achna, in a two-legged play-off for one spot in the 1991–92 Cypriot First Division. Enosis Neon Paralimni won both matches and secured their place in the 1991–92 Cypriot First Division.