| Official Name: | Sai Yai Subdistrict |
| Native Name: | Thai: ตำบลไทรใหญ่ |
| Settlement Type: | Subdistrict |
| Subdivision Type: | Country |
| Subdivision Type2: | Province |
| Subdivision Name2: | Nonthaburi |
| Subdivision Type3: | District |
| Subdivision Name3: | Sai Noi |
| Area Total Km2: | 43 |
| Area Footnotes: | [1] |
| Population As Of: | 2020 |
| Population Footnotes: | [2] |
| Population Total: | 6400 |
| Population Density Km2: | 148.84 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Postal Code Type: | Postal code |
| Blank Name: | TIS 1099 |
Sai Yai (Thai: ไทรใหญ่, in Thai pronounced as /sāj jàj/) is one of the seven subdistricts (tambon) of Sai Noi District, in Nonthaburi Province, Thailand. Neighbouring subdistricts are (from north clockwise) Sam Mueang, Rat Niyom, Khun Si, Bang Phasi, Sai Ngam and Ninlaphet. In 2020 it had a total population of 6,400 people.[2]
The subdistrict is subdivided into 11 administrative villages (muban).[3] [4]
| No. | Name | Thai | |
|---|---|---|---|
| 1. | Ban Krathum Muet | บ้านกระทุ่มมืด | |
| 2. | Ban Chao Fueang | บ้านเจ้าเฟื่อง | |
| 3. | Ban Plai Khlong Khun Si | บ้านปลายคลองขุนศรี | |
| 4. | Ban Bang O | บ้านบางโอ | |
| 5. | Ban Sai Yai | บ้านไทรใหญ่ | |
| 6. | Ban Sam Mueang | บ้านสามเมือง | |
| 7. | Ban Ming Khwan | บ้านมิ่งขวัญ | |
| 8. | Ban Khlong Song | บ้านคลองสอง | |
| 9. | Ban Mom Chaem (Ban Khlong Mom Chaem) | บ้านหม่อมแช่ม (บ้านคลองหม่อมแช่ม) | |
| 10. | Ban Khlong Nueng | บ้านคลองหนึ่ง | |
| 11. | Ban Mai | บ้านใหม่ |
The whole area of the subdistrict is covered by Sai Yai Subdistrict Administrative Organization (Thai: องค์การบริหารส่วนตำบลไทรใหญ่).