National Museum of American Diplomacy, Diplomacy museum at the Harry S Truman Building, Washington, United States

The National Museum of American Diplomacy is a museum housed within the Harry S. Truman Building in Washington, dedicated to the history of US foreign relations through documents, objects, and exhibits on international negotiations. The collection spans several centuries and draws on material from diplomatic missions around the world.

Ambassador Stephen Low and Senator Charles Mathias founded the Foreign Affairs Museum Council in 1999 to build the first museum devoted to American diplomacy. In 2000 Secretary of State Madeleine Albright agreed to house it at the Department of State, and Patrick F. Kennedy secured 20,000 square feet. The council became the Diplomacy Center Foundation in 2013; construction began in late 2014 and the pavilion was finished in 2017. It was renamed the National Museum of American Diplomacy in November 2019.

The museum displays personal items belonging to diplomats, including Madeleine Albright's pin collection, which she used during negotiations to send silent messages. These objects show how individual personalities shaped the work of diplomacy.

Visitors need a government-issued photo ID and must book an appointment before arriving, so planning ahead is essential. The entrance is on 21st Street on the State Department side of the building, so it helps to check the exact location before coming.

The museum holds a passport issued in 1798 to protect an American citizen traveling abroad, one of the oldest surviving examples of this kind of document in the country. It shows that the idea of protecting citizens overseas was part of diplomacy from very early on.