Adolf Hitler entered French territory for the first time in the war and visited the Canadian National Vimy Memorial, where photographers took his picture as he walked around the site with his entourage. The photos, showing the memorial intact, were then published in German newspapers to refute stories in the Canadian media claiming that the Germans had bombed it.
War Secretary Anthony Eden gave a radio address on the Dunkirk evacuation reporting that four-fifths of the British Expeditionary Force had been saved. "The British Expeditionary Force still exists, not as a handful of fugitives, but as a body of seasoned veterans," Eden said. "We have had great losses in equipment. But our men have gained immeasurably in experience of warfare and in self-confidence. The vital weapon of any army is its spirit. Ours has been tried and tempered in the furnace. It has not been found wanting. It is this refusal to accept defeat, that is the guarantee of final victory."
The remaining French forces at Dunkirk were pushed back into the town itself.
26,256 were evacuated from Dunkirk as operations switched to only being undertaken at night due to the costly air attacks.
The masked crimefighting character The Spirit first appeared in the American Sunday comics.
The Germans launched Operation Paula, an attempt to destroy the French Air Force. However, British intelligence had warned the French of the impending attack and the operation failed to achieve its strategic goals.
The last British troops were evacuated from Dunkirk.
German aerial bombing of Paris killed 45 people.
The Germans began the second phase of the invasion of France, codenamed Fall Rot, by attacking across the Somme and Aisne rivers. The Germans initially met stiff resistance, since the French had spent the past two weeks organizing their defenses south of the Somme.
A single airplane from the French Navy bombed Berlin in a night raid. The Farman 223.4 lingered over the city for as long as possible to create the impression of more than one airplane, then dropped its bomb load over some factories in Berlin's north end.
At 6 p.m., Benito Mussolini appeared on the balcony of the Palazzo Venezia to announce that in six hours, Italy would be in a state of war with France and Britain. After a speech explaining his motives for the decision, he concluded: "People of Italy: take up your weapons and show your tenacity, your courage and your valor."  The Italians had no battle plans of any kind prepared.
Anti-Italian riots broke out in major cities across the United Kingdom after Italy's declaration of war. Bricks, stones and bottles were thrown through the windows of Italian-owned shops, and 100 arrests were made in Edinburgh alone.
The Italian invasion of France began. Fighting would be mostly limited to skirmishing for the first ten days since both sides along the Franco-Italian border were deployed in defensive positions at the beginning of hostilities.
7th Panzer Division reached Dalles near Dieppe.
While making a commencement speech at the Memorial Gymnasium of the University of Virginia, President Roosevelt denounced Mussolini: "On this tenth day of June, 1940, the hand that held the dagger has plunged it into the back of its neighbor." The president also said that military victories for the "gods of force and hate" were a threat to all democracies in the western world and that America could no longer pretend to be a "lone island in a world of force."
The Anglo-French Supreme War Council met at a chateau in Briare which General Maxime Weygand was using as a military headquarters. Weygand wanted Churchill to send the entire Royal Air Force to France, but Churchill disagreed, saying that if the Germans would divert their air power to the skies over Britain, the French Army would get a chance to regroup. Churchill expressed determination to fight on until all of France's territory was recovered, no matter how much of it fell to the Germans in the interim, and suggested that the French could resort to guerrilla warfare if the time came when traditional military operations were no longer possible. The French were not receptive to this proposal, alarmed at the prospect of Paris being reduced to ruins while the general outcome of the war remained unchanged. Churchill brought up the question of what the French Navy would do if the Army suspended fighting, but Paul Reynaud ended the meeting by stating that the French were as determined to continue fighting as the British were.
The RAF conducted an overnight raid on Turin and Genoa. Bombs intended for the Fiat headquarters and manufacturing plant in Turin missed their targets and killed 14 civilians near the city center, an event the Italians publicized as an act of terrorism.
The Anglo-French Supreme War Council met for the final time, at Tours. Churchill encouraged the French to continue the fight from North Africa, but Reynauld sought British consent to seek an armistice with Germany instead, which Churchill refused to grant.
The Finnish-owned civilian Junkers Ju 52 passenger and transport plane Kaleva was shot down by two Soviet bombers while en route from Tallinn to Helsinki, killing all 9 on board. Finland did not protest the incident to the Soviets due to fear of a hostile response.
Philippe Pétain became Prime Minister of France after Paul Reynaud resigned. Only one hour after becoming the head of government, Pétain asked his Foreign Minister Paul Baudouin to pass a note to the Spanish ambassador asking Spain to request "the conditions Chancellor Hitler would require to put a halt to military operations and sign an armistice."
At 3:00a.m., Pétain's request to open peace negotiations reached Hitler's headquarters near Sedan. Hitler's aides were unsure whether to wake Hitler up, but his valet eventually did so and gave him the cable. Hitler was not surprised and had been expecting such a message for several days.
At 12:30p.m. Pétain took to the radio to deliver his first message to the nation: "It is with a heavy heart that I say to you that fighting must cease." However, fighting went on in some sectors.
The Germans bombed a railway complex at Rennes that was crowded with both military personnel and refugees trying to escape the fighting. A munitions train exploded during the attack and a total of 800 people were killed.
The troopship RMS Lancastria was sunk by German air attack off the port of Saint-Nazaire during Operation Ariel with over 4,000 fatalities. It is the greatest loss of life in the sinking of any British ship in history. Churchill ordered that news of the sinking be kept secret from the British public.
Hitler and Mussolini met in Munich to discuss the French armistice request. Mussolini hoped to present Hitler with a list of spoils that Italy wanted to get from the French, but was embarrassed when Hitler displayed no interest in discussing the matter at the time. Hitler also politely but firmly denied Mussolini's request to sit at the same table to sign the armistice with the French, leaving the Italians to seek out a separate one.
Appeal of 18 June: The BBC broadcast a speech by Charles de Gaulle. "Must we abandon all hope?," de Gaulle asked the French people. "Is our defeat final and irremediable? To those questions I answer - No! Speaking in full knowledge of the facts, I ask you to believe me when I say that the cause of France is not lost. The very factors that brought about our defeat may one day lead us to victory... I, General de Gaulle, now in London, call on all French officers and men who are at present on British soil, or may be in the future, with or without their arms; I call on all engineers and skilled workmen from the armaments factories who are at present on British soil, or may be in the future, to get in touch with me. Whatever happens, the flame of French resistance must not and shall not die."
The Germans captured Lorient, but not in time to stop all the seaworthy ships in its port from being scuttled.
The 5th Panzer Division captured Brest at 7 p.m.
Charles de Gaulle broadcast again over the BBC. "Faced by the bewilderment of my countrymen, by the disintegration of a government in thrall to the enemy, by the fact that the institutions of my country are incapable, at the moment, of functioning, I, General de Gaulle, a French soldier and military leader, realise that I now speak for France," he said. "In the name of France, I make the following solemn declaration: It is the bounden duty of all Frenchmen who still bear arms to continue the struggle. For them to lay down their arms, to evacuate any position of military importance, or agree to hand over any part of French territory, however small, to enemy control, would be a crime against our country. For the moment I refer particularly to French North Africa - to the integrity of French North Africa."
The Italian offensive in the Alps began at 5:30a.m. amid a freak snowstorm. 32 Italian divisions under the overall command of Crown Prince Umberto attacked 3 French divisions commanded by René Olry, but failed to make much progress.
The Germans entered La Rochelle, but not before all the seaport's naval facilities were blown up.
The Italian offensive reached the eastern approaches of Menton but was unable to advance any further.
De Gaulle made a third broadcast over the BBC. "Honour, common sense, and the interests of the country require that all free Frenchmen, wherever they be, should continue the fight as best they may," he declared. "It is therefore necessary to group the largest possible French force wherever this can be done. Everything which can be collected by way of French military elements and potentialities for armaments production must be organised wherever such elements exist. I, General de Gaulle, am undertaking this national task here in England. I call upon all French servicemen of the land, sea, and air forces; I call upon French engineers and skilled armaments workers who are on British soil, or have the means of getting here, to come and join me."
Peace talks commenced between the French and Italian delegations at the Villa Incisa near Rome. The French were prepared to walk out if the Italian demands were too harsh, but they were surprised at the leniency of the terms.
At 1:02a.m. the Republican Party nominated Wendell Willkie of Indiana as its candidate for President of the United States. A dark horse candidate with a background in business, Willkie had never held public office before but won the nomination because he was seen as a moderate whose views were the closest match to those of the electorate.
Willkie made his acceptance speech before the Republican convention, declaring, ""I stand before you without a single pledge or promise or understanding of any kind except for the advancement of your cause and the preservation of American democracy."