| Montaigu | |
| Commune Status: | Commune |
| Image Coat Of Arms: | Blason Montaigu aisne.svg |
| Arrondissement: | Laon |
| Canton: | Villeneuve-sur-Aisne |
| Insee: | 02498 |
| Postal Code: | 02820 |
| Mayor: | Caroline Mitouart[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Champagne Picarde |
| Coordinates: | 49.5364°N 3.8306°W |
| Elevation M: | 93 |
| Elevation Min M: | 71 |
| Elevation Max M: | 199 |
| Area Km2: | 23.51 |
Montaigu (in French pronounced as /mɔ̃tɛgy/) is a commune in the Aisne department in Hauts-de-France in northern France.