| Siwa Prommas | |
| Fullname: | Siwa Prommas |
| Birth Date: | 14 January 1994 |
| Birth Place: | Nakhon Si Thammarat, Thailand |
| Currentclub: | MOF Customs United |
| Clubnumber: | 6 |
| Position: | Left midfielder |
| Years1: | 2013 |
| Clubs1: | Samut Prakan United |
| Years2: | 2015 |
| Clubs2: | Rajpracha |
| Years3: | 2016–2019 |
| Clubs3: | Navy |
| Caps3: | 21 |
| Goals3: | 0 |
| Years4: | 2020– |
| Clubs4: | MOF Customs United |
Siwa Prommas (th| ศิวะ พรหมมาศ, born 6 October 1985) is a Thai professional footballer who plays as a left midfielder for the Thai League 2 club MOF Customs United.