| Sethiathoppu | |
| Other Name: | Sethiyathope |
| Settlement Type: | Panchayat town |
| Pushpin Map Hi: | India Tamil Nadu |
| Pushpin Map Caption: | Location in Tamil Nadu, India |
| Coordinates: | 11.26°N 79.32°W |
| Subdivision Type: | Country |
| Subdivision Name: |  India |
| Subdivision Type1: | State |
| Subdivision Name1: | Tamil Nadu |
| Subdivision Type2: | District |
| Subdivision Name2: | Cuddalore |
| Leader Title: | President |
| Leader Name: | K.V.Kulothungan |
| Unit Pref: | Metric |
| Area Total Km2: | 14 |
| Population Total: | 10,547 |
| Population As Of: | 2011 |
| Demographics Type1: | Languages |
| Demographics1 Title1: | Official |
| Demographics1 Info1: | Tamil |
| Timezone1: | IST |
| Utc Offset1: | +5:30 |
| Postal Code Type: | PIN |
| Postal Code: | 608702 |
| Area Code Type: | Telephone code |
| Area Code: | 91-04144 |
| Registration Plate: | TN-91(TN-31 till Jun 17,2015), Now TN -91. |
Sethiathoppu (in Tamil seːttijaːttoːppɯ/) is a panchayat town in Bhuvanagiri, Tamil Nadu. It is situated on a crossroads of the Chennai–Thanjavur (National Highway 24) highway. The town was established as a civilian town by the Cholas in the 11th century C.E. According to Tamil scholars, Sethiathoppu was formed as a settlement when Chola king Rajendra I moved his capital from Thanjavur to Gangaikonda Cholapuram, which lies 20 km south.
The town is named after Sethiyaar, a landlord, who used to own land in Thoppu, on the banks of the Vellar River.
According to the 2001 Census of India, Sethiyathoppu had a population of 7,962. Males constituted 52% of the population and females 48%. The town had an average literacy rate of 72%, higher than the national average of 59.5%; male literacy was 80% and female literacy was 64%. 10% of the population was under six years of age.[1]