Swissair Flight 111 (SR-111, SWR-111) was a Swissair McDonnell Douglas MD-11 on a scheduled airline flight from John F. Kennedy International Airport in New York City, United States to Cointrin International Airport in Geneva, Switzerland. This flight was also a codeshare flight with Delta Air Lines.

On September 2, 1998 the aircraft used for the flight, registered HB-IWF, crashed into the Atlantic Ocean southwest of Halifax International Airport at the entrance to St. Margarets Bay, Nova Scotia. The crash site was 8 kilometres (5 mi) from shore, roughly equidistant between the tiny fishing and tourist communities of Peggys Cove and Bayswater. All 229 people on board died.

The resulting investigation by the Transportation Safety Board of Canada (TSB) took over four years and cost CAD$57 million (at that time approximately US$39 million). The organization concluded that flammable material used in the aircraft's structure allowed a fire to spread beyond the control of the crew, resulting in the loss of control and crash of the aircraft.

Swissair Flight 111 was known as the "U.N. shuttle" due to its popularity with United Nations officials; the flight often carried business executives, scientists, and researchers.