The opening ceremony of the delayed 2020 Summer Olympics took place on 23 July 2021 at Olympic Stadium, Tokyo, and was formally opened by Emperor Naruhito. As mandated by the Olympic Charter, the proceedings combined the formal and ceremonial opening of this international sporting event, including welcoming speeches, hoisting of the flags and the parade of athletes, with an artistic spectacle to showcase the host nation's culture and history. The majority of the artistic spectacle was pre-recorded, with live segments performed adhering to social distancing to athletes, officials and a small VIP audience. The ceremony marked the 125th anniversary of the 1896 Summer Olympics in Athens—the inaugural edition of the modern Olympic Games.

The Olympic Games ceremonies of the Ancient Olympic Games were an integral part of these Games; the modern Olympic games have opening, closing, and medal ceremonies. Some of the elements of the modern ceremonies date back to the Ancient Games from which the Modern Olympics draw their ancestry. An example of this is the prominence of Greece in both the opening and closing ceremonies. During the 2004 Games, the medal winners received a crown of olive branches, which was a direct reference to the Ancient Games, in which the victor's prize was an olive wreath. The various elements of the ceremonies are mandated by the Olympic Charter, and cannot be changed by the host nation. This requirement of seeking the approval of the International Olympic Committee (IOC) includes the artistic portion of opening and closing ceremonies.