Windows on the World was a complex of dining, meeting, and entertainment venues on the top floors (106th and 107th) of the North Tower (Building One) of the original World Trade Center complex in Lower Manhattan, New York City, United States.

It included a restaurant called Windows on the World, a smaller restaurant called Wild Blue (before 1999 was called "Cellar in the Sky"), a bar called The Greatest Bar on Earth (which had previously been the Hors d'Oeuvrerie) as well as a wine school and conference and banquet rooms for private functions located on the 106th floor. Developed by restaurateur Joe Baum and designed initially by Warren Platner, Windows on the World occupied 50,000 square feet (4,600 m) of space in the North Tower. The Skydive Restaurant, which was a 180 seat cafeteria on the 44th floor of 1 WTC conceived for office workers, was also operated by Windows on the World.

The restaurants opened on April 19, 1976, and were destroyed in the September 11 attacks. All of the staff members who were present in the restaurant on the day of the attacks perished; the plane's impact severed all means of escape from the 92nd floor up.

The main dining room faced north and east, allowing guests to look out onto the skyline of Manhattan. The dress code required jackets for men and was strictly enforced; a man who arrived with a reservation but without a jacket was seated at the bar. The restaurant offered jackets that were loaned to the patrons so they could eat in the main dining room. The dinnerware, rugs, lighting fixtures, menus and the communication equipment were designed by Milton Glaser.

A more intimate dining room, Wild Blue, was located on the south side of the restaurant. The bar extended along the south side of 1 World Trade Center as well as the corner over part of the east side. Looking out from the bar through the full length windows, one could see views of the southern tip of Manhattan, where the Hudson and East Rivers meet. In addition, one could see the Liberty State Park with Ellis Island and Staten Island with the Verrazzano-Narrows Bridge. The kitchens, utility spaces, and conference center in the restaurant were located on the 106th floor.

Windows on the World closed after the 1993 bombing, in which employee Wilfredo Mercado was killed while checking in deliveries in the building's underground garage. The explosion also damaged receiving areas, storage and parking spots used by the restaurant complex. On May 12, 1994, the Port Authority of New York and New Jersey announced that the Joseph Baum & Michael Whiteman Company had won the contract to run the restaurants after Windows's former operator, Inhilco, gave up its lease. It underwent a US$25 million renovation and reopened on June 26, 1996. Cellar in the Sky, a 60-seat space within the restaurant, reopened after Labor Day. In 1999, Cellar in the Sky was changed into an American steakhouse and renamed "Wild Blue". In 2000, its final full year of operation, it reported revenues of US$37 million, making it the highest-grossing restaurant in the United States.

The executive chefs of Windows on the World included Philippe Feret of Brasserie Julien while the last chef was Michael Lomonaco.

Windows on the World was destroyed when the North Tower collapsed during the terrorist attacks of September 11, 2001. While the restaurant was hosting regular breakfast patrons and the Risk Waters Financial Technology Congress, Egyptian terrorist Mohamed Atta and four other Al-Qaeda hijackers crashed American Airlines Flight 11 into the North Tower between floors 93 and 99 at 8:46 a.m. Everyone present in the restaurant died that day, as all means of escape (including the stairwells and elevators leading down from the impact zones) were instantly severed by the impact. Victims trapped in Windows on the World either died from smoke inhalation from the ensuing fire, jumping or falling to their deaths from the restaurant, or being killed in the eventual collapse of the North Tower. At least five Windows occupants were witnessed jumping or falling to their deaths from the restaurant.

There were 72 restaurant staff present in the restaurant, including assistant general manager Christine Olender, whose desperate calls to Port Authority police represented the restaurant's final communications. Sixteen Incisive Media-Risk Waters Group employees, as well as 76 other guests/contractors, were also present. Among those also present was the executive director of the Port Authority, Neil Levin, who was having breakfast. After about 9:40 a.m., no further distress calls from the restaurant were made. The last people to leave the restaurant before Flight 11 crashed into the North Tower at 8:46 a.m. were Michael Nestor, Liz Thompson, Geoffrey Wharton, and Richard Tierney, who all shared an elevator together. They departed at 8:44 a.m. and survived the attack.

World Trade Center lessor, Larry Silverstein, was regularly holding breakfast meetings in Windows on the World with tenants as part of his recent acquisition of the Twin Towers from the Port Authority, and was scheduled to be in the restaurant on the morning of the attacks. However, his wife insisted that he had to go to a dermatologist's appointment that morning, whereby he avoided death.

In its last iteration, Windows on the World received mixed reviews. Ruth Reichl, a New York Times food critic, said in December 1996 that "nobody will ever go to Windows on the World just to eat, but even the fussiest food person can now be content dining at one of New York's favorite tourist destinations." She gave the restaurant two out of four stars, signifying a "very good" quality rather than "excellent" (three stars) or "extraordinary" (four stars). In his 2009 book Appetite, William Grimes wrote that "At Windows, New York was the main course." In 2014, Ryan Sutton of Eater.com compared the now-destroyed restaurant's cuisine to that of its replacement, One World Observatory. He stated, "Windows helped usher in a new era of captive audience dining in that the restaurant was a destination in itself, rather than a lazy byproduct of the vital institution it resided in."

Windows of Hope Family Relief Fund was organized soon after the attacks to provide support and services to the families of those in the food, beverage, and hospitality industries who had been killed on September 11 in the World Trade Center. Windows on the World executive chef Michael Lomonaco and owner-operator David Emil were among the founders of that fund.

On January 4, 2006, a number of former Windows on the World staff opened Colors, a co-operative restaurant in Manhattan that serves as a tribute to their colleagues and whose menu reflects the diversity of the former Windows' staff. The original location closed in 2017 and reopened in 2019. Windows on the World was planned to reopen on the top floors of the new One World Trade Center, but that project was canceled in 2011. Instead, One World Observatory contains eateries named ONE Dine, ONE Mix and ONE Café.

It has been speculated that The Falling Man, a famous photograph of a man dressed in white falling headfirst on September 11, was an employee at Windows on the World. Although his identity has never been conclusively established, he was believed to be Jonathan Briley, an audio technician at the restaurant. Jonathan was the younger brother of Alex Briley, the original "G.I." from the band Village People .

In March 2005, the novel Windows on the World, by French novelist Frédéric Beigbeder, was released; the novel focuses on two brothers who are in the restaurant on September 11 with their father. Kenneth Womack's 2012 novel The Restaurant at the End of the World is a fictive recreation of the lives of the staff and visitors at the Windows on the World complex on the morning of September 11.

In 2023 A novel published by Alan Gratz called Ground Zero is about a kid named Brandon who is with his father in the Windows Of The World On the morning of September 11th.

• List of tenants in 1 World Trade Center (1971–2001)
• Top of the World Trade Center Observatories

• Windows on the World (Archive)
  • Archived snapshot of the former WotW website, August 2, 2002
  • Last pre-9/11 archived snapshot of the former WotW website, February 1, 2001
  • Photographs of WotW