The World at War was a Thames Television documentary television series which assessed many aspects of World War II and events which led up to it and which followed in its wake. It was narrated by Sir Laurence Olivier. There are 26 hour-long episodes (52 minutes excluding commercials; in the UK it was screened with only one central break).

Producer Jeremy Isaacs asked a historian to list 15 key campaigns of the war and devoted one episode to each. The remaining 11 episodes were devoted to other issues such as home life in Britain and Germany, the experience of occupation in The Netherlands, and of course the Nazis' use of genocide.

A great deal of footage and interviews that was not used in the original series was later made into additional hour or half-hour documentaries narrated by Eric Porter. These are included in the DVD set of the series.

The series was originally transmitted on the ITV network in the United Kingdom between 31 October 1973 and 8 May 1974, and it has subsequently been shown around the world; the most recent repeat showings in the UK have been on BBC Two. The series is often viewed as the definitive television history of the Second World War, although at the time of its production many aspects of the war remained secret e.g. the history of the breaking of the Enigma code machine, and the development of the Colossus computer to decrypt Enigma's successor, the Lorenz or "fish" encryption system.

The 26 episodes were:-

  • 1 A New Germany - 1933-39
  • 2 Distant War - 1939-40
  • 3 France Falls - May-June 1940
  • 4 Alone - Britain May 1940-June 1941
  • 5 Barbarossa
  • 6 Banzai - Japan Strikes
  • 7 On Our Way - America Enters the War
  • 8 Desert - The War in North Africa
  • 9 Stalingrad
  • 10 Wolfpack: U-Boats in the North Atlantic 1939-43
  • 11 Red Star - The Soviet Union 1941-43
  • 12 Whirlwind
  • 13 Tough Old Gut
  • 14 It's a Lovely Day Tomorrow
  • 15 Home Fires
  • 16 Inside the Reich - Germany 1940-44
  • 17 Morning
  • 18 Occupation
  • 19 Pincers
  • 20 Genocide
  • 21 Nemesis
  • 22 Japan - 1941-45
  • 23 Pacific - The Island to Island War
  • 24 The Bomb
  • 25 Reckoning
  • 26 Remember

Points to add: names of key interviewees, transfer of archive footage to 16mm, extensive use of colour footage, influenced by BBC "Great War" series (see World War I)