| Tournament details | |
|---|---|
| Country | Singapore |
| Dates | April 2009 - November 2009 |
| Teams | 16 |
| Final positions | |
| Champions | Geylang United |
| Runner-up |  Bangkok Glass |
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The Singapore Cup 2009 (known as the RHB Singapore Cup due to its main sponsor) started on 27 April 2009. It was the 12th staging of the annual Singapore Cup tournament.
12 S.League clubs and 4 invited foreign teams from Thailand (2 teams), Cambodia (1) and Indonesia (1) played in this edition. The cup was a single-elimination tournament, with all sixteen teams playing from the first round. The first round involved one-off matches. Subsequent rounds involved ties of two legs.
The final was played on 8 November and won by Geylang United, who beat Bangkok Glass 1–0.
The cup winner were guaranteed a place in the 2010 AFC Cup.