The 1990–91 Cypriot Fourth Division was the sixth season of the Cypriot fourth-level football league. The championship was split into three geographical groups, representing the Districts of Cyprus. The winners were:
- Nicosia-Keryneia Group: AEK Kakopetrias
- Larnaca-Famagusta Group: Achyronas Liopetriou
- Limassol-Paphos Group: Kentro Neotitas Maroniton
The three winners were promoted to the 1991–92 Cypriot Third Division. Seven teams were relegated to regional leagues.