| Official Name: | On Tai |
| Native Name: | ออนใต้ |
| Settlement Type: | Tambon |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type2: | Province |
| Subdivision Name2: | Chiang Mai |
| Subdivision Type3: | District |
| Subdivision Name3: | San Kamphaeng |
| Population As Of: | 2005 |
| Population Total: | 5371 |
| Timezone: | ICT |
| Utc Offset: | +7 |
On Tai (Thai: ออนใต้) is a tambon (subdistrict) of San Kamphaeng District, in Chiang Mai Province, Thailand.[1] In 2005 it had a population of 5,371 people. The tambon contains 11 villages.