Gladwyne is an affluent suburban community in Montgomery County, Pennsylvania, United States along the historic Philadelphia Main Line. In 2011, Gladwyne was ranked the 7th richest zip code in the country in a study by Bloomberg BusinessWeek. The population was 4,050 at the 2000 census. As Gladwyne is neither an incorporated area nor a census-designated place, all data are for the ZIP code 19035, with which the community is .
There are four churches, a synagogue, a library, two schools, the Gladwyne fire company, the Gladwyne Civic Association, the Stony Lane Swim Club, playgrounds, parks, businesses, and retail shops within the confines of Gladwyne. The historic Guard House Inn is also located within Gladwyne.The village is also home to the Philadelphia Country Club on its periphery, Merion Cricket Club, and to The Courts a private tennis club. Because the town was early to preserve space and has received many donations of land, developers have not subdivided the area into more typical suburban developments, so the area retains a mixture of farm, colonial town, and late 19th/early 20th housing uncharacteristic of other Main Line communities.
Banker James Crosby Brown of Brown Brothers & Co. built a estate that later was divided into non-divisible (deed-restricted) lots of three to , an early act of (partial) preservation that set an important precedent for future acts by both individuals and the township. The Lower Merion Conservancy plays a significant role in protecting the local heritage and maintains its office in Gladwyne's Rolling Hill Park.