| Official Name: | Martinsburg Junction, Pennsylvania |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Pennsylvania#USA |
| Pushpin Label: | Martinsburg Junction |
| Pushpin Label Position: | top |
| Coordinates: | 40.31°N -78.3367°W |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Pennsylvania |
| Subdivision Type2: | County |
| Subdivision Name2: | Blair |
| Subdivision Type3: | Township |
| Subdivision Name3: | North Woodbury |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Sq Mi: | 0.10 |
| Area Land Sq Mi: | 0.10 |
| Area Water Sq Mi: | 0.00 |
| Area Total Km2: | 0.26 |
| Area Land Km2: | 0.26 |
| Area Water Km2: | 0.00 |
| Population As Of: | 2020 |
| Population Footnotes: | [2] |
| Population Total: | 35 |
| Population Density Sq Mi: | 343.14 |
| Population Density Km2: | 132.28 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 1340 |
| Postal Code Type: | ZIP Code |
| Postal Code: | 16662 (Martinsburg) |
| Area Code: | 814/582 |
| Blank Name: | FIPS code |
| Blank Info: | 42-47880 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2805521 |
Martinsburg Junction is an unincorporated community and census-designated place (CDP) in Blair County, Pennsylvania, United States. It was first listed as a CDP prior to the 2020 census.
The CDP is in southeastern Blair County, in the northwestern part of North Woodbury Township. It is in the Morrisons Cove region of the county, one-half mile west of the borough of Martinsburg.