| Thandalai | |
| Settlement Type: | village |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location in Tamil Nadu, India |
| Subdivision Type: | Country |
| Subdivision Name: |  India |
| Subdivision Type1: | State |
| Subdivision Name1: | Tamil Nadu |
| Subdivision Type2: | District |
| Subdivision Name2: | Ariyalur |
| Unit Pref: | Metric |
| Population Total: | 5310 |
| Population As Of: | 2001 |
| Population Density Km2: | auto |
| Demographics Type1: | Languages |
| Demographics1 Title1: | Official |
| Demographics1 Info1: | Tamil |
| Timezone1: | IST |
| Utc Offset1: | +5:30 |
| Postal Code Type: | PIN |
| Postal Code: | 621803 |
| Area Code Type: | Telephone code |
| Area Code: | 04331 |
| Registration Plate: | TN- |
| Blank1 Name Sec1: | Coastline |
| Blank1 Info Sec1: | 0km (00miles) |
| Blank2 Name Sec1: | Nearest city |
| Blank2 Info Sec1: | Trichy |
| Blank3 Name Sec1: | Sex ratio |
| Blank3 Info Sec1: | 1.054 ♂/♀ |
| Blank4 Name Sec1: | Literacy |
| Blank4 Info Sec1: | 62.07% |
Thandalai is a village in the Udayarpalayam taluk of Ariyalur district, Tamil Nadu, India.Government higher secondary school is located in Thandalai village.
As per the 2001 census, Thandalai had a total population of 5310 with 2729 males and 2581 females.[1]