| Grantham River | |
| Mouth Location: | Waiau Uwha River |
| Subdivision Type1: | Country |
| Subdivision Name1: | New Zealand |
| Pushpin Map: | New Zealand |
| Pushpin Map Caption: | Location of the mouth within New Zealand |
The Grantham River is a river in the Canterbury region of New Zealand. It arises in the Hanmer Range near Mount Miromiro, in the Hanmer Forest Park, and flows south-east into the Waiau Uwha River, which has its mouth on the Pacific Ocean.[1]
A thermal spring on the river is undeveloped.[2]