美国总统就职典礼的举行，标志着新一届美国总统任期的开始。实际上，美国宪法中对就职典礼所规定的唯一一项，就是在总统进入总统办公室执政前，必须进行宣誓。然而随着历史的推移，就职典礼的传统项目也逐渐扩大，已从最初一个简单的就职宣誓仪式，发展成为如今一个包括游行、演讲和舞会的为期一天的活动。

宣誓当天，被称为就职典礼日（Inauguration Day），是美国联邦的公共假期。从1793年至1933年为3月4日，从1937年之后，就职日为1月20日（1933年批准的美国宪法第二十修正案改变了任期的开始日期）。

The inauguration of the president of the United States is a ceremonial event marking the commencement of a new four-year term of a president of the United States. The day a presidential inauguration occurs is known as "Inauguration Day" and occurs on January 20 (or 21st if the 20th is a Sunday). (Prior to the Twentieth Amendment, the date was March 4, the day of the year on which the Constitution of the United States first took effect in 1789; the last inauguration to take place on the older date was Franklin D. Roosevelt's first one on March 4, 1933.) The most recent public presidential inauguration ceremony, the swearing in of President Barack Obama to begin his second four-year term in office, took place on Monday, January 21, 2013.