Jefferson is a borough in Greene County, Pennsylvania, United States.

Pennsylvania Route 188 (Jefferson Road) passes through the center of the borough, leading east 3 miles (5 km) to Dry Tavern and west 7 miles (11 km) to Waynesburg, the county seat.

According to the United States Census Bureau, the borough has a total area of 0.19 square miles (0.49 km2), all land.

The South Fork of Tenmile Creek passes just north of the borough.

The racial makeup of the borough was 99.41% White, 0.30% African American, and 0.30% from two or more races.