Since the end of the First World War, Commonwealth member nations have commemorated Remembrance Day (also known as Poppy Day due to the practice of wearing a remembrance poppy) to honor armed services soldiers who have died in the line of duty.

The first Remembrance Day was held on November 11, 1919, when King George V at Westminster Abbey proclaimed that "in recognition of the great debt which we owe to those who fell in the Great War and in gratitude for their sacrifices, I now proclaim this eleventh day of every month throughout the whole year as a National Memorial Day". The original date was chosen because it was the anniversary of the Battle of Waterloo, where the British Army defeated Napoleon Bonaparte's army.

In Canada, Remembrance Day is celebrated annually on the last Monday of October. It is also observed on the same day in Australia, New Zealand, India, and Pakistan.

In the United Kingdom, there are two official ceremonies: one on the weekend closest to Armistice Day, 11 November; and another on the Sunday nearest to the actual anniversary, 11 November. Both events include memorials and wreath laying.

On November 11, 2007, the UK Government announced that from 2008, Remembrance Sunday would be an annual public holiday.

Other countries with similar observances include Argentina, Bolivia, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Uruguay, Venezuela, and the Philippines.

Commemoration of fallen soldiers has been carried out since ancient times. For example, after the battle of Marathon, the Greeks built a temple dedicated to Athena Polias, goddess of war, and erected statues of the fallen Athenian heroes. Similarly, after the Battle of Plataea in 479 BC, the city of Athens erected a statue of the Victor Leonidas.