December 16 - Billy Hamilton, American baseball player (b. 1866)
December 21 - F. Scott Fitzgerald, American writer (b. 1896)
December 22 - Nathanael West, American writer (b. 1903)
December 25 - Agnes Ayres, American actress (b. 1898)
Events
January 5 - FM radio is demonstrated to the FCC for the first time.
January 6 - Mass execution of Poles, committed by Germans in the city of Poznań, Warthegau.
January 8 - World War II: Britain introduces food rationing.
January 12 - World War II: Soviets bombs cities in Finland.
January 29 - Three gasoline multiple units carrying factory workers crash and explode while approaching Ajikawaguchi station, Yumesaki Line (Nishinari Line), Osaka, Japan, killing at least 181 people and injuring at least 92.
February 2 - Frank Sinatra debuts with the Tommy Dorsey orchestra.
February 16 - World War II: Altmark Incident: The German tanker Altmark is boarded by sailors from the British destroyer HMS Cossack. 299 British prisoners are freed.
February 27 - Martin Kamen and Sam Ruben discover carbon-14
February 28 - Basketball is televised for the first time (Fordham University vs. the University of Pittsburgh in Madison Square Garden).
February 29 - For her role as Mammy in Gone with the Wind, Hattie McDaniel becomes the first African American to win an Academy Award.
February 29 - Finland initiates Winter War peace negotiations
February 29 - In a ceremony held in Berkeley, California, because of the war, physicist Ernest Lawrence receives the 1939 Nobel Prize in Physics from Sweden's Consul General in San Francisco.
March 3 - Five people are killed in an arson attack on the offices of the communist newspaper Norrskensflamman in Luleå, Sweden.
March 5 - Members of Soviet politburo sign an order for the execution of 25,700 Polish intelligentsia, including 14,700 Polish POWs, known also as the Katyn massacre.
March 6 - Winter War: An armistice is signed by Finland and the Soviet Union.
March 12 - Winter War: Finland signs the Moscow Peace Treaty with the Soviet Union, ceding almost all of Finnish Karelia. Finnish troops and the remaining population is immediately evacuated.
March 23 - The Lahore Resolution (Qarardad-e-Pakistan or the then Qarardad-e-Lahore) is put forward at the Annual General Convention of the All India Muslim League.
March 28 - Construction begins of the exhibition center to host the Thessaloniki International Trade Fair.
March 30 - Sino-Japanese War: Japan declares Nanking to be the capital of a new Chinese puppet government, nominally controlled by Wang Ching-wei.
April 7 - Booker T. Washington becomes the first African American to be depicted on a United States postage stamp.
April 8 - World War II: Great Britain and France announce that they have mined Norwegian territorial waters to prevent their use by German supply ships.
April 9 - World War II: Germany invades Denmark and Norway.
April 14 - World War II: Royal Marines land in Namsos, Norway in preparation for a larger force to arrive two days later.
April 15 - The Allies begin their attack on the Norwegian town of Narvik which is occupied by Nazi Germany.
April 23 - The Rhythm Night Club fire at a dance hall in Natchez, Mississippi, kills 198 people.
May 1 - The 1940 Summer Olympics are cancelled due to war.
May 5 - World War II: In London, a Norwegian government-in-exile is formed.
May 6 - John Steinbeck is awarded the Pulitzer Prize for his novel The Grapes of Wrath.
May 9 - World War II: The German submarine U-9 sinks the French coastal submarine Doris near Den Helder.
May 10 - World War II: The first German bombs of the war fall on England at Chilham and Petham, in Kent.
May 10 - World War II: Germany invades Belgium, the Netherlands, and Luxembourg.
May 10 - World War II: Winston Churchill is appointed Prime Minister of the United Kingdom.
May 10 - World War II: Invasion of Iceland by the United Kingdom.
May 13 - World War II: Germany's conquest of France begins as the German army crosses the Meuse River. Winston Churchill makes his "blood, toil, tears, and sweat" speech to the House of Commons.
May 13 - Queen Wilhelmina of the Netherlands flees the Nazi invasion in the Netherlands to Great Britain. Princess Juliana takes her children to Canada for their safety.
May 14 - World War II: Rotterdam is bombed by the German Luftwaffe.
May 14 - World War II: The Netherlands surrenders to Germany.
May 15 - USS Sailfish (SS-192) recomisioned, origionaly the Squalus.
May 15 - World War II: After fierce fighting, the poorly trained and equipped Dutch troops surrender to Germany, marking the beginning of five years of occupation.
May 15 - McDonald's opens its first restaurant in San Bernardino, California.
May 17 - World War II: Germany occupies Brussels, Belgium.
May 17 - World War II: the old city centre of the Dutch town of Middelburg is bombed by the German Luftwaffe, to force the surrender of the Dutch armies in Zeeland.
May 20 - Holocaust: The first prisoners arrive at a new concentration camp at Auschwitz.
May 24 - Igor Sikorsky performs the first successful single-rotor helicopter flight.
May 25 - World War II: The Battle of Dunkirk begins.
May 26 - World War II: Battle of Dunkirk – In France, Allied forces begin a massive evacuation from Dunkirk, France.
May 27 - World War II: In the Le Paradis massacre, 97 soldiers from a Royal Norfolk Regiment unit are shot after surrendering to German troops.
May 28 - World War II: Belgium surrenders to Germany.
May 28 - World War II: Norwegian, French, Polish and British forces recapture Narvik. This is the first allied infantry victory of World War II.
June 1 - The Leninist Communist Youth League of the Karelo-Finnish SSR holds its first congress.
June 3 - World War II: The Battle of Dunkirk ends with a German victory and with Allied forces in full retreat.
June 4 - World War II: The Dunkirk evacuation ends
June 10 - World War II: Italy declares war on France and the United Kingdom.
June 10 - World War II: U.S. President Franklin D. Roosevelt denounces Italy's actions with his "Stab in the Back" speech at the graduation ceremonies of the University of Virginia.
June 10 - World War II: German forces, under General Erwin Rommel, reach the English Channel.
June 10 - World War II: Canada declares war on Italy.
June 10 - World War II: Norway surrenders to German forces.
June 11 - World War II: British forces bomb Genoa and Turin in Italy.
June 11 - World War II: First attack of the Italian Air force on the island of Malta.
June 12 - World War II: 13,000 British and French troops surrender to Field Marshal Erwin Rommel at Saint-Valery-en-Caux.
June 14 - World War II: Paris falls under German occupation, and Allied forces retreat.
June 14 - A group of 728 Polish political prisoners from Tarnów become the first residents of the Auschwitz concentration camp.
June 16 - World War II: Marshal Henri Philippe Pétain becomes Premier of Vichy France.
June 16 - A Communist government is installed in Lithuania.
June 26 - World War II: under the Molotov-Ribbentrop Pact, the Soviet Union presents an ultimatum to Romania requiring it to cede Bessarabia and the northern part of Bukovina.
June 28 - Romania cedes Bessarabia (current-day Moldova) to the Soviet Union.
July 2 - Indian independence leader Subhas Chandra Bose is arrested and detained in Calcutta.
July 5 - World War II: The United Kingdom and the Vichy France government break off diplomatic relations.
July 10 - World War II: Vichy France government is established.
July 20 - U.S. President Franklin D. Roosevelt signs the Hatch Act of 1939, limiting political activity by Federal government employees.
July 23 - United States' Under Secretary of State Sumner Welles's declaration on the U.S. non-recognition policy of the Soviet annexation and incorporation of three Baltic States
July 25 - General Guisan orders the Swiss Army to resist German invasion and makes surrender illegal.
July 27 - The animated short A Wild Hare is released, introducing the character of Bugs Bunny.
July 31 - A doodlebug train in Cuyahoga Falls, Ohio collides with a multi-car freight train heading in the opposite direction, killing 43 people.
August 3 - World War II: Italy invades British Somaliland.
August 5 - World War II: Latvia is annexed by the Soviet Union.
August 7 - Alsace Lorraine is annexed by the Third Reich (Germany) during World War II
August 8 - The "Aufbau Ost" directive is signed by Wilhelm Keitel.
August 13 - World War II: Battle of Britain begins
August 16 - World War II: The Communist Party is banned in German-occupied Norway.
August 20 - In Mexico City exiled Russian revolutionary Leon Trotsky is fatally wounded with an ice axe by Ramon Mercader. He dies the next day.
August 26 - Chad is the first French colony to join the Allies under the administration of Félix Éboué, France's first black colonial governor.
September 4 - World War II: a German submarine makes the first attack against a United States ship (the USS Greer) .
September 7 - Treaty of Craiova: Romania loses Southern Dobrudja to Bulgaria.
September 11 - George Stibitz pioneers the first remote operation of a computer.
September 11 - World War II: Buckingham Palace is damaged during a German air raid.
September 12 - Cave paintings are discovered in Lascaux, France.
September 12 - An explosion at the Hercules Powder Company plant in Kenvil, New Jersey kills 51 people and injures over 200.
September 13 - World War II: German bombs damage Buckingham Palace.
September 15 - World War II: The climax of the Battle of Britain, when the Royal Air Force shoots down large numbers of Luftwaffe aircraft.
September 16 - Sam Rayburn is elected Speaker of the United States House of Representatives. He is widely regarded as the most effective Speaker of the House in American history.
September 18 - World War II: Italian troops conquer Sidi Barrani.
September 19 - Witold Pilecki is voluntarily captured and sent to Auschwitz in order to smuggle out information and start a resistance.
September 27 - World War II: The Tripartite Pact is signed in Berlin by Germany, Japan and Italy.
October 1 - The Pennsylvania Turnpike, often considered the first superhighway in the United States, opens to traffic.
October 4 - Meeting between Adolf Hitler and Benito Mussolini at the Brenner Pass.
October 7 - World War II: the McCollum memo proposes bringing the United States into the war in Europe by provoking the Japanese to attack the United States.
October 14 - Balham tube disaster during the Blitz.
October 16 - Benjamin O. Davis Sr. is named the first African American general in the United States Army.
October 16 - Holocaust: The Warsaw Ghetto is established.
October 26 - The P-51 Mustang makes its maiden flight.
October 28 - World War II: Italy invades Greece through Albania, marking Greece's entry into World War II. It is celebrated in Greece as Okhi Day (Όχι=No) Day.
October 31 - World War II: The Battle of Britain ends
November 5 - Franklin D. Roosevelt is elected to a third term as President of the United States.
November 7 - In Tacoma, Washington, the original Tacoma Narrows Bridge ("Galloping Gertie") collapses in a windstorm, a mere four months after the bridge's completion.
November 10 - Walt Disney begins serving as an informer for the Los Angeles office of the FBI; his job is to report back information on Hollywood subversives.
November 11 - The German cruiser Atlantis captures top secret British mail, and sends it to Japan.
November 11 - Armistice Day Blizzard: An unexpected blizzard kills 144 in U.S. Midwest.
November 14 - World War II: In England, the city of Coventry is heavily bombed by German Luftwaffe bombers. Coventry Cathedral is almost completely destroyed.
November 16 - World War II: In response to Germany's leveling of Coventry, England two days before, the Royal Air Force bombs Hamburg.
November 16 - Holocaust: In occupied Poland, the Nazis close off the Warsaw Ghetto from the outside world.
November 18 - World War II: German leader Adolf Hitler and Italian Foreign Minister Galeazzo Ciano meet to discuss Benito Mussolini's disastrous invasion of Greece.
November 18 - New York City's Mad Bomber places his first bomb at a Manhattan office building used by Consolidated Edison.
November 20 - World War II: Hungary, Romania and Slovakia join the Axis Powers.
November 22 - World War II: Following the Italian invasion, Greek troops advances into Albanian soil and capture Korytsa.
November 25 - First flight of the deHavilland Mosquito and Martin B-26 Marauder.
November 27 - In Romania, the ruling party Iron Guard arrests and executes over 60 of exiled King Carol II of Romania's aides, including former minister Nicolae Iorga.
November 27 - World War II: At the Battle of Cape Spartivento, the Royal Navy engages the Regia Marina in the Mediterranean Sea.
November 30 - Lucille Ball marries Desi Arnaz in Greenwich, Connecticut.
December 7 - The first prototype Fairey Barracuda flew
