Pennsburg is a borough in Montgomery County, Pennsylvania, United States. Its population was 3,889 at the 2020 census. It is part of the Upper Perkiomen School District. It is also part of the strip of small towns that run together along Route 29: Red Hill, Pennsburg, and East Greenville. The towns are collectively referred to as Upper Perk.

Pennsburg is located at 40°23′44″N 75°29′50″W / 40.39556°N 75.49722°W / 40.39556; -75.49722 (40.395595, −75.497361). According to the U.S. Census Bureau, the borough has a total area of 0.8 square miles (2.1 km²), all land. Pennsburg is located 40 mi (64 km) northwest of Philadelphia and 5 mi (8.0 km) southwest of Quakertown. Pennsburg's elevation is at 350 ft (110 m) above sea level. A nature preserve is along Macoby Creek.

The borough has a hot-summer, humid continental climate (Dfa) and average monthly temperatures range from 29.9 °F in January to 74.6 °F in July. The USDA hardiness zone is 7a.

As of the 2020 census, Pennsburg had a population of 3,889.

The median age was 33.4 years. 25.4% of residents were under the age of 18 and 12.2% of residents were 65 years of age or older. For every 100 females there were 101.5 males, and for every 100 females age 18 and over there were 98.4 males age 18 and over.

100.0% of residents lived in urban areas, while 0.0% lived in rural areas.

There were 1,289 households in Pennsburg, of which 34.7% had children under the age of 18 living in them. Of all households, 47.2% were married-couple households, 19.9% were households with a male householder and no spouse or partner present, and 22.3% were households with a female householder and no spouse or partner present. About 25.1% of all households were made up of individuals and 8.5% had someone living alone who was 65 years of age or older.

There were 1,352 housing units, of which 4.7% were vacant. The homeowner vacancy rate was 1.6% and the rental vacancy rate was 4.3%.