Gladwyne is a suburban community in Lower Merion Township, Montgomery County, Pennsylvania, United States along the historic Philadelphia Main Line.

In 2018, Gladwyne was ranked the sixth richest ZIP Code (using 2015 IRS data) in the country in a study by Bloomberg BusinessWeek.

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 185-acre (0.75 km2) estate that later was divided into non-divisible (deed-restricted) lots of three to 17 acres (6.9 ha), an early act of (partial) preservation that set an important precedent for future acts by both individuals and the township.

[3] The Lower Merion Conservancy plays a significant role in protecting the local heritage and maintains its office in Gladwyne's Rolling Hill Park.

After the American Civil War and following construction of the Pennsylvania Railroad's Main Line west from Center City, wealthy Philadelphians located many of their summer homes there.

[4] The development of the Schuylkill Expressway (I-76) in the 1960s and the subsequent development of King of Prussia as a major business center increased Gladwyne's appeal, as it was the Main Line town situated closest to the Expressway and midway between King of Prussia and Center City Philadelphia.

Yet the core of the village, built originally at the convergence of Youngsford and Righter's Mill Roads during the latter part of the eighteenth century, remained essentially the same, allowing Gladwyne to retain all of its original historic character and at the same time enjoy the conveniences of modern suburban living, such as a centrally located supermarket with ample parking, pharmacy, tavern, and restaurants.