| Competition: | Cypriot Fourth Division |
| Season: | 1990–91 |
| Winners: | AEK Kakopetrias Kentro Neotitas Maroniton Achyronas Liopetriou |
| Promoted: | AEK Kakopetrias Kentro Neotitas Maroniton Achyronas Liopetriou |
| Relegated: | AEK Kythreas APOP Palechoriou APEA Akrotiriou Panikos & Sokratis Zakakiou Kimonas Xylotympou Evagoras Avgorou Omonia Ormideia |
| Prevseason: | 1989–90 |
| Nextseason: | 1991–92 |
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:
The three winners were promoted to the 1991–92 Cypriot Third Division. Seven teams were relegated to regional leagues.