| Tergnier | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Tergnier (Aisne).svg |
| Arrondissement: | Laon |
| Canton: | Tergnier |
| Insee: | 02738 |
| Postal Code: | 02700 |
| Party: | PCF |
| Mayor: | Michel Carreau[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CA Chauny Tergnier La Fère |
| Coordinates: | 49.6564°N 3.2883°W |
| Elevation M: | 53 |
| Elevation Min M: | 44 |
| Elevation Max M: | 90 |
| Area Km2: | 17.98 |
Tergnier (pronounced as /fr/) is a commune in the department of Aisne, Hauts-de-France, France. Its location on the Canal de Saint-Quentin and the Creil–Jeumont railway (Tergnier station) supported its development as an industrial centre in the second half of the 19th century.
The commune of Tergnier absorbed the former communes of Fargniers and Vouël in 1973, and Quessy in 1991. Since the 2020 municipal elections, Michel Carreau has been the mayor of Tergnier.
Tergnier is twinned with the municipality of Wolfhagen (Germany) since 17 May 1981.[2]
The population data in the table and graph below refer to the commune of Tergnier proper, in its geography at the given years, i.e. excluding former communes that were absorbed at a later date.