The International Children's Day (ICD) is celebrated in numerous countries, usually (but not always) on June 1 each year.

The ICD had its origin in the World Conference for the Wellbeing of Children in Geneva, Switzerland in 1925. It is not clear as to why June 1 was chosen as the ICD: one theory has it that the Chinese consul-general in San Francisco (USA) gathered a number of Chinese orphans to celebrate the Dragon Boat Festival in 1925, which happened to be on June 1 that year, and also coincided with the conference in Geneva.

June 1 has since been observed as the ICD by numerous countries, especially by Communist countries; in the Western world the ICD is usually celebrated on other days of the year (if at all), and there is often little public awareness about these celebrations. (See the section on Germany below for further discussions.) Consequently there is sometimes a misperception that June 1 as the ICD was a Communist invention. Nonetheless, in recent years even some groups within the United States started observing the ICD on June 1.