Germantown is an urbanized census-designated place in Montgomery County, Maryland, United States. With a population of 91,249 as of the 2020 census, it is the third most populous place in Maryland, after Baltimore and Columbia. Germantown is located approximately 28 miles (45 km) outside the U.S. capital of Washington, D.C., and is an important part of the Washington metropolitan area.

Germantown was founded in the early 19th century by European immigrants, though much of the area's development did not take place until the mid-20th century. The original plan for Germantown divided the area into a downtown and six town villages: Gunners Lake Village, Kingsview Village, Churchill Village, Middlebrook Village, Clopper's Mill Village, and Neelsville Village. The Churchill Town Sector at the corner of Maryland Route 118 and Middlebrook Road most closely resembles the center of Germantown because of the location of the Upcounty Regional Services Center, the Germantown Public Library, the Black Rock Arts Center, the Regal Germantown Stadium 14, and pedestrian shopping that features an array of restaurants. Three exits to Interstate 270 are less than one mile away, the Maryland Area Regional Commuter train is within walking distance, and the Germantown Transit Center that provides Ride On shuttle service to the Shady Grove station of the Washington Metro's Red Line.

Germantown has the assigned ZIP codes of 20874 and 20876 for delivery and 20875 for post office boxes. It is the only "Germantown, Maryland" recognized by the United States Postal Service, though three other Maryland counties have unincorporated communities with the same name.