| Montarnaud | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason ville fr Montarnaud (Hérault).svg |
| Arrondissement: | Lodève |
| Canton: | Gignac |
| Insee: | 34163 |
| Postal Code: | 34570 |
| Mayor: | Jean-Pierre Pugens[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Vallée de l'Hérault |
| Coordinates: | 43.65°N 3.6997°W |
| Elevation Min M: | 95 |
| Elevation Max M: | 315 |
| Area Km2: | 27.53 |
Montarnaud (in French pronounced as /mɔ̃taʁno/) is a commune in the Hérault department in the Occitanie region in southern France.
Montarnaud has a mediterranean climate (Köppen climate classification Csa). The average annual temperature in Montarnaud is . The average annual rainfall is with October as the wettest month. The temperatures are highest on average in July, at around, and lowest in January, at around . The highest temperature ever recorded in Montarnaud was on 28 June 2019; the coldest temperature ever recorded was on 16 January 1985.