| 1st January 1939 | The Hewlett-Packard Company is founded and becomes the largest technology company in the world. |
| 6th February 1939 | Prime Minister Neville Chamberlain officially declares that any German attack on France will also be considered an attack on Great Britain. |
| 21st February 1939 | The Golden Gate International Exposition opens in San Francisco, California. |
| 2nd March 1939 | Pope Pius XII (Cardinal Pacelli) succeeds Pope Pius XI as the 260th Pope. |
| 28th March 1939 | Dictator Francisco Franco assumes power in Madrid. |
| 1st April 1939 | The Spanish Civil War comes to an end when the last of the Republican forces surrender. |
| 14th April 1939 | John Steinbeck's classic novel “The Grapes of Wrath” is published for the first time. |
| 17th May 1939 | King George VI and Queen Elizabeth arrive in Quebec City in Canada, to begin the first ever tour of the country by Canada's monarch. |
| 17th June 1939 | Murderer Eugen Weidmann is decapitated by the guillotine in the last public guillotining to take place in France. |
| 24th June 1939 | The government of Siam changes its name to Thailand, which means 'Free Land'. |
| 25th August 1939 | An IRA bomb explodes in the centre of Coventry, killing five people. |
| 1st September 1939 | Nazi Germany invades Poland, thus beginning the Second World War in Europe. |
| 3rd September 1939 | The United Kingdom, France, New Zealand and Australia declare war on Germany. |
| 8th November 1939 | Adolf Hitler narrowly escapes an assassination attempt in Munich by Georg Elser, while celebrating the sixteenth anniversary of the Beer Hall Putsch. |
| 16th November 1939 | Al Capone is released from Alcatraz prison. |
| 27th December 1939 | The 1939 Erzincan earthquake kills 30,000 people in Eastern Anatolia, Turkey. The earthquake features seven powerful tremors and one of these tremors is measured at 8.2 on the Richter scale of magnitude. |