| Petit Morin | |
| Map: | Petitt Morin.png |
| Mouth Coordinates: | 48.9439°N 3.1222°W |
| Subdivision Type1: | Country |
| Length: | 86km (53miles) |
The Petit Morin (in French pronounced as /pəti mɔʁɛ̃/, literally Little Morin) is an 86km (53miles) river in France, a left tributary of the Marne. Its source is in the commune Val-des-Marais. Its course crosses the departments of Marne, Aisne and Seine-et-Marne. It flows westwards through the towns of Montmirail, Villeneuve-sur-Bellot, Saint-Cyr-sur-Morin and Jouarre, finally flowing into the Marne in La Ferté-sous-Jouarre.