Henry Davis Sleeper (March 27, 1878 – September 22, 1934) was an American antiquarian, collector, and interior decorator best known for Beauport, his Gloucester, Massachusetts, country home that is "one of the most widely published houses of the twentieth century.

[2] Sleeper was introduced to the Eastern Point in Gloucester, Massachusetts, in the spring of 1906 by the Harvard economist A. Piatt Andrew, who later served in the U.S. House of Representatives, who had built a handsome summer mansion, Red Roof, on a rock ledge above the harbor.

[2] Eastern Point was an enclave occupied by a somewhat louche group of "Bohemian" artists and intellectuals with frequent visits from some of the more colorful and unconventional members of Boston society, in particular Isabella Stewart Gardner, the legendary art collector and builder of Fenway Court in the Back Bay Fens, now the Isabella Stewart Gardner Museum.

[1] He salvaged Gothic windows from a church, various fireplaces and doorways from homes in Connecticut and Rhode Island, and a 3 and one-eight inch thick "Indian-repelling door" from Deerfield, Massachusetts.

[2] In 1918, Sleeper became the U.S. Representative of, and a major fundraiser for, the American Field Service, an ambulance corps founded by A. Piatt Andrew early in World War I.

[7] While Andrew served in the battle zones, Sleeper crisscrossed the Atlantic with supplies and funds, and worked closely with the French military.

Isabella Stewart Gardner commissioned work from him; Henry Francis du Pont engaged his assistance with the big new wing of the family's massive Delaware house, Winterthur, now a famed museum of American decorative arts;[1] he designed for Hollywood stars Joan Crawford and Fredric March.

As he had no direct descendants, Beauport was sold to Helena Woolworth McCann, the daughter of Frank Winfield Woolworth, who was contacted by Henry Francis Du Pont urging that Sleeper's rooms remain exactly as they were as the value of the house and its collection of art objects depended primarily on their being left unchanged.