The retelling of June 6, 1944, from the perspectives of the Germans, US, British, Canadians, and the Free French. Marshall Erwin Rommel, touring the defenses being established as part of the Reich's Atlantic Wall, notes to his officers that when the Allied invasion comes they must be stopped on the beach. "For the Allies as well as the Germans, it will be the longest day"
| Directing | Ken Annakin | Director |
| Directing | Andrew Marton | Director |
| Writing | Cornelius Ryan | Screenplay |
| Production | Darryl F. Zanuck | Producer |
| Sound | Maurice Jarre | Original Music Composer |
| Camera | Jean Bourgoin | Director of Photography |
| Camera | Walter Wottitz | Director of Photography |
| Editing | Samuel E. Beetley | Editor |
| Writing | Cornelius Ryan | Novel |
| Directing | Bernhard Wicki | Director |
| Production | Maude Spector | Casting |
| Art | Léon Barsacq | Art Direction |
| Art | Ted Haworth | Art Direction |
| Art | Vincent Korda | Art Direction |
| Crew | Johnny Borgese | Special Effects |
| Production | Elmo Williams | Associate Producer |
| Art | Gabriel Béchir | Set Designer |
| Writing | Romain Gary | Writer |
| Writing | James Jones | Writer |
| Writing | David Pursall | Writer |
| Writing | Jack Seddon | Writer |
| Crew | Paul Anka | Additional Music |
| Sound | Mitch Miller | Music Arranger |
| Sound | Joseph de Bretagne | Sound |
| Sound | Jacques Maumont | Sound |
| Sound | William Robert Sivel | Sound |
| Directing | Bernard Farrel | Assistant Director |
| Directing | Tom Pevsner | Assistant Director |
| Directing | Louis Pitzele | Assistant Director |
| Directing | Gérard Renateau | Assistant Director |
| Crew | Jean Fouchet | Special Effects |
| Crew | Günther Blumentritt | Technical Advisor |
| Crew | James Gavin | Technical Advisor |
| Crew | John Howard | Technical Advisor |
| Crew | Philippe Kieffer | Technical Advisor |
| Crew | Pierre Koenig | Technical Advisor |
| Crew | Helmuth Lang | Technical Advisor |
| Crew | The Earl of Lovat | Technical Advisor |
| Crew | Frederick Morgan | Technical Advisor |
| Crew | Max Pemsel | Technical Advisor |
| Crew | Werner Pluskat | Technical Advisor |
| Crew | Josef Priller | Technical Advisor |
| Crew | Lucie Maria Rommel | Technical Advisor |
| Crew | Friedrich Ruge | Technical Advisor |
| Crew | Jean Barral | Technical Advisor |
| Crew | Roger Bligh | Technical Advisor |
| Crew | Willard L. Bushy | Technical Advisor |
| Crew | Hubert Deschard | Technical Advisor |
| Crew | A. J. Hillebrand | Technical Advisor |
| Crew | James R. Johnson | Technical Advisor |
| Crew | Fernand Prevost | Technical Advisor |
| Crew | E. C. Peake | Technical Advisor |
| Crew | Albert Saby | Technical Advisor |
| Crew | Joseph B. Seay | Technical Advisor |
| Directing | Gerd Oswald | Director |
| Directing | Darryl F. Zanuck | Director |
| Directing | Henry Wise | Second Assistant Director |
| Directing | Jean Herman | Assistant Director |
| Directing | Gerd Oswald | Second Unit Director |
| Directing | Henry Sokal Jr. | Assistant Director |
| Directing | Elmo Williams | Second Unit Director |
| Crew | Karl Baumgartner | Special Effects |
| Crew | Joseph de Bretagne | Special Effects |
| Crew | Gerald Endler | Special Effects |
| Crew | Karl Helmer | Special Effects |
| Crew | Augie Lohman | Special Effects |
| Crew | R.A. MacDonald | Special Effects |
| Crew | Fernando Pérez | Special Effects |
| Crew | Alex Weldon | Special Effects |
| Crew | Paul Wurtzel | Special Effects |
| Visual Effects | Wally Veevers | Visual Effects |
| Crew | Ken Buckle | Stunts |
| Crew | Yvan Chiffre | Stunts |
| Crew | Jack Cooper | Stunts |
| Crew | Gil Delamare | Stunts |
| Crew | Jean-Pierre Janic | Stunts |
| Crew | Gérard Moisan | Stunts |
| Crew | Joe Powell | Stunts |
| Crew | Nosher Powell | Stunts |
| Crew | Alexandre Renaud | Stunts |
| Crew | John Sullivan | Stunts |
| Crew | Lionel Vitrant | Stunts |
| Crew | Ian Yule | Stunts |
