Gladys Moore Vanderbilt, Countess Széchenyi, was an American heiress from the Vanderbilt family and wife of Hungarian Count László Széchenyi.

The Vanderbilt family is an American family who gained prominence during the Gilded Age. Their success began with the shipping and railroad empires of Cornelius Vanderbilt, and the family expanded into various other areas of industry and philanthropy. Cornelius Vanderbilt's descendants went on to build grand mansions on Fifth Avenue in New York City; luxurious "summer cottages" in Newport, Rhode Island; the palatial Biltmore House in Asheville, North Carolina; and various other opulent homes. The family also built Berkshire cottages in the western region of Massachusetts; examples include Elm Court.