| Louis Puissant | |
| Birth Date: | 22 September 1769 |
| Birth Place: | Le Châtelet-en-Brie, France |
| Death Place: | Paris, France |
| Nationality: | French |
| Occupation: | topographical engineer, geodesist, and mathematician |
| Spouses: | Françoise Coutet |
| Children: | Louis (1793–1836) |
Louis Puissant (22 September 1769, in Le Châtelet-en-Brie – 10 January 1843, in Paris) was a French topographical engineer, geodesist, and mathematician.
He was appointed an officer in the corps of topographical engineers (ingénieurs géographes) of l'armée des Pyrénées occidentales in 1792 and then a professor in l’école centrale d'Agen in 1796. From October 1802 to August 1803, he was in charge of geodesic triangulations on the island of Elba and then in 1803–1804 in Lombardy. He was elected a member of l'Société Philomathique de Paris in 1810 and a member of l'Académie des sciences in 1828.
In addition to numerous scientific memoirs, he was the author of several books on geodesy and mathematics.
His marriage to Françoise Coutet produced a son, Louis (1793–1836), who graduated from l'École polytechnique.