| 8th January 1940 | Food rationing begins in Great Britain as a result of the Second World War. |
| 18th March 1940 | Adolf Hitler and Benito Mussolini meet at Brenner Pass in the Alps and agree to form an alliance against France and the United Kingdom. |
| 7th April 1940 | Booker T. Washington - an educator, author and leading figure in African-American communities - becomes the first black man to be depicted on an American postage stamp. |
| 10th May 1940 | Neville Chamberlain resigns as Prime Minster and Winston Churchill replaces him.. |
| 4th June 1940 | British forces successfully complete the evacuation of 300,000 troops from Dunkirk in France. |
| 4th June 1940 | Winston Churchill tells the British House of Commons, "We shall not flag or fail. We shall fight on the beaches...on the landing grounds...in the fields and the streets...We shall never surrender." |
| 10th June 1940 | Italy declares war on France and the United Kingdom. |
| 14th June 1940 | Paris falls under German occupation. |
| 10th July 1940 | The Battle of Britain begins. The German Air Force attempt to gain air superiority, but the Royal Air Force stand firm. This is the Nazi Germans’ first defeat in the Second World War and thus a turning point of the war. |
| 20th August 1940 | Winston Churchill pays tribute to the Royal Air Force in the House of Commons: "Never in the field of human conflict was so much owed by so many to so few." |
| 7th September 1940 | Nazi Germany begins to rain bombs on London in the first of fifty-seven consecutive nights of strategic bombing, known as the Blitz. |
| 9th November 1940 | Neville Chamberlain, former Prime Minister of the United Kingdom (b. 1869) dies. |
| 11th November 1940 | Battle of Taranto: The Royal Navy launches the first all-aircraft carrier strike in history, on the Italian fleet at Taranto. |
| 14th November 1940 | Coventry is destroyed by five-hundred German Air Force bombers using a total of 150,000 fire bombs, 503 tons of high explosives, and 130 parachute mines. 568 people are killed. |
| 12th December 1940 | The City of Sheffield is badly damaged by German air-raids. |
| 21st December 1940 | F. Scott Fitzgerald, American writer (b. 1896) dies from a second heart-attack. |
| 29th December 1940 | Second Great Fire of London: Luftwaffe, the German Air force, carries out a massive incendiary bombing raid, starting 1,500 fires. Many famous buildings, including the Guildhall and Trinity House, are either damaged or destroyed. |