Armistice Day is the anniversary of the symbolic end of World War I on 11 November 1918. It commemorates the armistice signed between the Allies and Germany at Rethondes, France, for the cessation of hostilities on the Western Front, which took effect at eleven o'clock in the morning - the "eleventh hour of the eleventh day of the eleventh month". While this official date to mark the end of the war reflects the cease fire on the Western Front, hostilities continued in other regions, especially across the former Russian Empire and in parts of the old Ottoman Empire.

The date was declared a national holiday in many allied nations, to commemorate those members of the armed forces who were killed during war. An exception is Italy, where the end of the war is commemorated on 4 November, the day of the Armistice of Villa Giusti. Called Armistice Day in many countries, it was known as National Day in Poland (also a public holiday) called Polish Independence Day. After World War II, the name of the holiday was changed to Veterans Day in the United States and to Remembrance Day in countries of the British Commonwealth of Nations. Armistice Day remains an official holiday in France. It is also an official holiday in Belgium, known also as the Day of Peace in the Flanders Fields.

In many parts of the world people take a two minute moment of silence at 11:00 a.m. as a sign of respect for the roughly 20 million who died in the war, as suggested by Edward George Honey in a letter to a British newspaper although Wellesley Tudor Pole established two ceremonial periods of remembrance based on events in 1917 (for further information see “Two Minute Silence”).