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. The population was 4,071 at the 2010 US 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 coterminous.