| Third Brook | |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | New York |
| Source1 Location: | Delaware County, New York |
| Mouth: | West Brook |
| Mouth Location: | Walton, New York, Delaware County, New York, United States |
| Mouth Coordinates: | 42.1675°N -75.1378°W |
| Basin Size: | 5.65sqmi |
Third Brook flows into West Brook by Walton, New York.[1]