| Official Name: | Petersham, Massachusetts |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Massachusetts#USA |
| Pushpin Label: | Petersham |
| Coordinates: | 42.4883°N -72.1869°W |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Name1: | Massachusetts |
| Subdivision Type2: | County |
| Subdivision Name2: | Worcester |
| Subdivision Type3: | Town |
| Subdivision Name3: | Petersham |
| Area Footnotes: | [1] |
| Area Total Sq Mi: | 1.23 |
| Area Land Sq Mi: | 1.23 |
| Area Water Sq Mi: | 0.00 |
| Area Total Km2: | 3.20 |
| Area Land Km2: | 3.20 |
| Area Water Km2: | 0.00 |
| Population As Of: | 2020 |
| Population Density Km2: | 70.42 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation M: | 334 |
| Postal Code Type: | ZIP Code |
| Postal Code: | 01366 |
| Area Code: | 351/978 |
| Blank Name: | FIPS code |
| Blank Info: | 25-53085 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2630529 |
| Population Total: | 225 |
| Unit Pref: | Imperial |
| Population Density Sq Mi: | 182.33 |
Petersham is a census-designated place (CDP) comprising the main village in the town of Petersham, Worcester County, Massachusetts, United States. Massachusetts Route 32 passes through the village, leading north 9miles to Athol and southeast 7miles to Barre. Massachusetts Route 122 joins Route 32 in the village center, leading southeast with it to Barre but northwest to Orange.
As of the 2010 census, the population of the CDP was 243, out of 1,234 in the entire town of Petersham.