Glassmanor is an unincorporated community and census-designated place located in Prince George's County, Maryland, in the United States. As of the 2020 census, the area had a population of 18,430 residents.
Historically, the United States Census Bureau grouped Glassmanor with the adjacent community of Oxon Hill as the "Oxon Hill-Glassmanor" census-designated place for statistical purposes during the 1990 and 2000 censuses. The community was last delineated as a separate entity in 1980, at which time it recorded a population of 7,751.