The John F. Kennedy assassination and the subsequent conspiracy theories surrounding it have been discussed, referenced, or recreated in popular culture numerous times.
The assassination has also been the subject of many time travel and alternate history stories in science fiction film, television and literature, many with Kennedy and/or Oswald surviving or other people in the Presidential limousine dead. Some of these have Governor John Connally or Jacqueline Kennedy killed in place of President Kennedy.
Literature
Novels
Gideon's March (Hodder & Stoughton) by J. J. Marric is fictional novel published in 1962, the year before the Kennedy assassination. In the book, Inspector George Gideon learns of a plot to assassinate President Kennedy during a state visit to London. The assassination is to take place during a parade, by means of a bomb; the assassin, called O'Hara, is a Southern bigot who hates the President for his Roman-Catholic faith and his civil-rights initiatives.
J. G. Ballard wrote a 1967 short-short story titled "The assassination of John Fitzgerald Kennedy considered as a downhill motor race."
The Illuminatus! Trilogy (1975) by Robert Shea and Robert Anton Wilson depicts the assassination scene, with several would-be assassins trying to kill Kennedy simultaneously.
Sherlock Holmes in Dallas (Dodd, Mead, & Co. 1980) by Edmund Aubrey, brings the renowned consulting detective out of his Sussex retirement to investigate the Kennedy assassination.
Libra (1988) by Don DeLillo is a fictional imagining of the assassination, with Lee Harvey Oswald as the protagonist.
The Underworld USA Trilogy (1995-2009) by James Ellroy, particularly the 1995 novel American Tabloid, constructs a fictional narrative involving several characters who have part in the Kennedy assassination.
In Columbo: The Grassy Knoll (1994) by William Harrington, the titular lieutenant solves the Kennedy Assassination after a talk-show host is murdered before an exposé.
The 1996 Doctor Who spin-off novel Who Killed Kennedy features the Doctor's enemy the Master attempting to kill Oswald before the assassination as Kennedy's survival would trigger a chain reaction in history that could wipe the Doctor from existence, requiring journalist James Stevens to go back in time and kill Kennedy himself (acting as both gunmen at different points in his life, as Oswald's rifle had a misaligned targeting scope that prevented him delivering the fatal shot from the Book Depository on the first trip). It should also be noted that coincidentally, the TV show this book is based on started the day after the assassination with the first episode delayed by eighty seconds due to news coverage of the killing.
The Star Spangled Contract (1976) by District Attorney Jim Garrison, and Captains and the Kings by Taylor Caldwell, are both based, in part, on a conspiratorial view of the Kennedy assassination.
In The Amnesia Desk by Jim Sullivan, the son of Kennedy's 'real' killer - a CIA assassin - has to flee from the Amnesia Desk, a CIA clean-up team.
Joshua, Son of None by Nancy Mars Freedman (1973, ISBN-13 9789995585228) is a novel about government officials secretly cloning Kennedy after assassination, and duplicating his actual life events by staging them in the new person's life. By controlling both nature and nurture, genetics and life events, the desired outcome results: the young man is successful, and is elected President.
Comic books
In the first album of Jean van Hamme and William Vance's comic book series XIII, the title character is shown to be the alleged assassin of fictional U.S. President William B. Sheridan, who was murdered in his car during an official presidential visit to a city. The events are clearly based on JFK's assassination.
In the Ultimate Marvel universe, Kennedy's true assassin is Red Skull, the son of Captain America. Nick Fury muses that the assassination of Kennedy was the Skull's way of showing that he would no longer take orders from America.
In the 2008–2009 series The Umbrella Academy: Dallas by Gerard Way and Gabriel Bá, the Kennedy assassination is a central plot element. The series initially takes place in a timeline where the assassination never happened, until an organisation of time-travelling assassins go back to 1963 to kill Kennedy. When the Umbrella Academy intercept the gunmen, The Rumour, disguised as Jacqueline Kennedy, uses her powers to make Kennedy's head explode.