The Kennedy Curse refers to several misfortunes suffered by one of America’s most prominent political families, the Kennedys. Unnatural deaths and unfortunate events have also extended to those related to the Kennedys by marriage, such as Jacqueline Kennedy Onassis and her two step-children from her marriage to Aristotle Onassis. In the context of conspiracy theories, the Kennedy Curse is believed to be the result of an actual hex cast against the family as some sort of vendetta. Most people use the term "Kennedy Curse" as a metaphor for the series of tragedies that have befallen the family, which is thought to be mostly due to their access to excess as one of the most prestigious families in the world.

An adventurous and competitive family, many of the Kennedys were avid aviators, and as such, many of the deaths and dangerous incidents included in the Kennedy Curse involve airplanes. As early as 1944, Joseph P. Kennedy, Jr., older brother to John F. Kennedy and Robert F. Kennedy, was killed when the plane he was flying on a World War II mission exploded over the English Channel. His sister, Kathleen Kennedy Cavendish, died in a plane crash in France four years later. In 1964, Massachusetts Senator Ted Kennedy became the first Kennedy to survive a plane crash, while his nephew, Robert F. Kennedy’s son, Joseph P. Kennedy II, found himself hostage on a plane hijacked by Palestinians in 1972. Finally, in 1999, John F. Kennedy, Jr.; his wife, Carolyn Bessette-Kennedy; and his sister-in-law, Lauren Bessette, died tragically when their private plane crashed in the Atlantic Ocean en route to Martha's Vineyard.

One of the most famous and beloved Kennedys by marriage, Jacqueline Kennedy Onassis, also suffered a series of misfortunes after her induction into the family. In 1954, Kennedy Onassis suffered a miscarriage, and two years later she gave birth to a stillborn daughter, who is buried beside her at Arlington National Cemetery and was reportedly to be named Arabella. In 1963, Kennedy Onassis was again overcome by loss when her son, Patrick Bouvier Kennedy, died two days after birth. A decade later, after she had re-married to Greek shipping magnate, Aristotle Onassis, Kennedy Onassis’ new stepson, Alexander Onassis, died in a plane crash. In 1988, Kennedy Onassis lost another stepchild, Christina Onassis, to heart failure related to substance abuse.

Perhaps the most devastating and memorable examples of the Kennedy Curse are the public assassinations of United States President John F. Kennedy in 1963, and his brother, Robert F. Kennedy, in 1968. Both died from gunshot wounds and their deaths were said to mark the end of an era known as "Camelot," a term coined by Jacqueline Kennedy Onassis to describe a time of happiness.

Several nephews of the late John F. Kennedy have also died or been injured under unusually tragic circumstances, succumbing to the so-called Kennedy Curse. In 1973, 12-year-old Edward Kennedy, Jr., son of Ted Kennedy, lost his right leg to bone cancer. Two of Robert and Ethel Kennedy’s sons have suffered untimely deaths, including David Kennedy, who died from a cocaine and Demerol overdose in 1984, and Michael Kennedy, who died in a skiing accident in 1997 after he collided with a tree during a game of ski football.