"Superdelegate" is an informal term for some of the delegates to the Democratic National Convention, the presidential nominating convention of the United States Democratic Party.

Unlike most convention delegates, the superdelegates are not selected based on the party primaries and caucuses in each U.S. state, in which voters choose among candidates for the party's presidential nomination. Instead, superdelegates are seated automatically, based solely on their status as current or former elected officeholders and party officials. They are free to support any candidate for the nomination.

The Democratic Party rules do not use the term "superdelegate". The formal designation (in Rule 9.A) is "unpledged party leader and elected official delegates" ("PLEO"). In addition to these unpledged PLEO delegates, the state parties choose other unpledged delegates (Rule 9.B) and pledged PLEO delegates (Rule 9.C). This article discusses only the unpledged PLEO delegates.

The Republican Party also seats some party officials as delegates without regard to primary or caucus results, but the term "superdelegate" is most commonly applied only in the Democratic Party.

At the 2008 Democratic National Convention the superdelegates will make up approximately one-fifth of the total number of delegates. The closeness of the race between the leading contenders, Hillary Rodham Clinton and Barack Obama, has increased the chance that the superdelegates will play a decisive role in selecting the nominee, a prospect that has caused unease among some Democratic Party leaders.