New York World's Fair, the name of two expositions presented in New York City. The site of both fairs was Flushing Meadow on Long Island. The first fair opened on April 30, 1939, the 150th anniversary of George Washington's first inauguration as President of the United States. It was open during the summers of 1939 and 1940, and had the theme “The World of Tomorrow.” Its architectural symbols were the Perisphere, a white sphere 200 feet (60 m) in diameter; and the Trylon, a triangular obelisk 700 feet (213 m) high. Sixty nations presented exhibits at the Fair.

The second New York World's Fair opened on April 22, 1964, the year that marked the 300th anniversary of the transfer of New Amsterdam from Dutch to English rule and its renaming as New York. The theme of the fair was “Peace Through Understanding.” Sixty-five nations presented exhibits during the summers of 1964 and 1965. The fair's symbol was a giant steel structure called the Unisphere, representing “Man's Achievement in an Expanding Universe.” Attendance exceeded 51,000,000.

An earlier international exposition, the first held in the United States, took place in New York in 1853. It was called the Exhibition of the Industry of All Nations, but was commonly called the Crystal Palace Exhibition, after the building in which it was held.