The first inauguration of Richard Nixon as the 37th president of the United States was held on Monday, January 20, 1969, at the East Portico of the United States Capitol in Washington, D.C. This was the 46th inauguration and marked the commencement of the first and eventually only full term of both Richard Nixon as president and Spiro Agnew as vice president. Chief Justice Earl Warren administered the presidential oath of office to Nixon, and Senate Minority Leader Everett Dirksen administered the vice presidential oath to Agnew. Nixon had narrowly defeated Hubert Humphrey, the incumbent vice president, in the presidential election. Nixon became the first non-incumbent vice president to be inaugurated as president, something that would not happen again until Joe Biden in 2021. This was also the last presidential oath administered by Chief Justice Warren.

The oath of office of the president of the United States is the oath or affirmation that the president of the United States takes upon assuming office. The wording of the oath is specified in Article II, Section One, Clause 8, of the United States Constitution, and a new president must take it before exercising or carrying out any official powers or duties.