| Rank | LW | Release
| Gross | %± LW | Theaters | Change | Average | Total Gross | Weeks | Distributor
| New This Week
| Estimated
|
|---|
| 1 | 1 | G.I. Joe: The Rise of Cobra | $415,346 | -52.8% | 143 | -74 | $2,904 | $1,820,989 | 2 | United International Pictures | false | false |
| 2 | - | Raging Phoenix | $259,902 | - | 125 | - | $2,079 | $443,029 | 1 | Mongkol Film Company | true | false |
| 3 | - | In Country Melody 2 | $131,365 | - | 79 | - | $1,662 | $252,313 | 1 | Pranakorn Films | true | false |
| 4 | 3 | Harry Potter and the Half-Blood Prince | $26,369 | -63% | 35 | -28 | $753 | $4,037,127 | 5 | Warner Bros. | false | false |
| 5 | 5 | The Taking of Pelham 123 | $22,561 | -57% | 31 | -4 | $727 | $331,985 | 3 | Sony Pictures Releasing | false | false |
| 6 | - | Trail of the Panda 2009 Re-release | $18,426 | - | 11 | - | $1,675 | $72,107 | 1 | Walt Disney Pictures | true | false |
| 7 | 4 | Nee Dtaam Galileo | $17,037 | -72.3% | 22 | -29 | $774 | $871,926 | 4 | N/A | false | false |
| 8 | - | Orphan | $15,179 | - | 30 | - | $505 | $17,877 | - | Warner Bros. | - | false |
| 9 | 7 | The Hangover | $13,884 | -23.2% | 5 | -4 | $2,776 | $101,130 | 3 | Warner Bros. | false | false |
| 10 | 2 | Death Happen | $10,397 | -86.8% | 35 | -23 | $297 | $465,463 | 3 | Mongkol Film Company | false | false |
| 11 | 6 | Sam Chuk | $9,711 | -75% | 43 | -13 | $225 | $69,309 | 2 | N/A | false | false |
| 12 | 8 | Brüno | $8,743 | -24.6% | 3 | - | $2,914 | $54,274 | 3 | Mongkol Major | false | false |
| 13 | 10 | Public Enemies | $3,390 | -55.7% | 4 | -16 | $847 | $329,907 | 4 | United International Pictures | false | false |
| 14 | 11 | Transformers: Revenge of the Fallen | $2,134 | +8.1% | 4 | - | $533 | $5,914,899 | 8 | United International Pictures | false | false |
| 15 | 9 | Solstice | $1,349 | -85% | 6 | -13 | $224 | $14,099 | 2 | Mongkol Major | false | false |
| 16 | - | The Wedding Game | $872 | - | 1 | - | $872 | $1,055 | 1 | Mongkol Major | true | false |
| 17 | 12 | Echelon Conspiracy | $765 | -41.9% | 2 | -3 | $382 | $8,971 | 3 | N/A | false | false |
| 18 | - | Baby and I | $709 | - | 1 | - | $709 | $971 | 1 | M Pictures | true | false |
| 19 | 15 | Departures | $654 | +4% | 1 | - | $654 | $28,320 | 9 | Mongkol Major | false | false |
| 20 | 16 | Public Enemy | $397 | -32.4% | 1 | - | $397 | $3,045 | 3 | M Pictures | false | false |
| 21 | 17 | April Bride | $224 | -39.1% | 1 | - | $224 | $2,641 | 4 | N/A | false | false |
