Public holidays in Japan (国民の祝日, kokumin no shukujitsu) were first established by the Public Holiday Law (国民の祝日に関する法律, Kokumin no Shukujitsu ni Kansuru Hōritsu; lit. 'An Act on public holidays'; Act No. 178 of 1948) of 1948. It has since been amended 11 times to add additional holidays, the latest being in 2018, for a total of 16 recognized holidays.

Article 3 of this law specifies that when a national holiday falls on a Sunday, the next working day shall become a public holiday, known as furikae kyūjitsu (振替休日; "compensatory public holiday", literally "substitute holiday"). Article 3 also determines that any day that falls between two other national holidays shall also become a holiday, known as kokumin no kyūjitsu (国民の休日; literally "citizens' holiday"). May 4, sandwiched between Constitution Memorial Day on May 3 and Children's Day on May 5, was an annual example of such a holiday until it was replaced by Greenery Day in 2007.

Although it is not an official holiday, most companies voluntarily designate a holiday from December 29 to January 3, or, depending on the industry, from Christmas Eve to January 5. This case is unique in Asia.

The national holidays in 2018–2026 are as follows.

In addition to the annual holidays listed above, certain events of celebration or mourning related to the imperial family are also treated as national holidays in the year in which they occur.

There have been six instances of such holidays since the introduction of the Public Holiday Law:

Beginning in 2000, Japan implemented the Happy Monday System, which moved a number of national holidays to Monday in order to obtain a long weekend.

In 2006, the country added Shōwa Day, a new national holiday, in place of Greenery Day on April 29, and to move Greenery Day to May 4. These changes took effect in 2007.