"Superdelegate" is an informal term commonly used 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, most of the superdelegates are seated automatically, based solely on their status as current or former party leaders and elected officials ("PLEOs"). Others are chosen during the primary season. All the superdelegates are free to support any candidate for the nomination.

The Democratic Party rules do not use the term "superdelegate". This article follows the most common media practice in using the term "superdelegate" to refer to unpledged delegates, who fall into two categories:

• delegates seated based on other positions they hold, who are formally described (in Rule 9.A) as "unpledged party leader and elected official delegates"^[1] (unpledged PLEO delegates); and
• additional unpledged delegates selected by each state party (in a fixed predetermined number), who are formally described (in Rule 9.B) as "unpledged add-on delegates" and who need not hold any party or elected position before their selection as delegates.^[1]

Unpledged PLEO delegates should not be confused with pledged PLEOs. Under Rule 9.C, the pledged PLEO slots are allocated to candidates based on the results of the primaries and caucuses.^[1] Another big difference between pledged PLEOs and unpledged PLEOs is that number of the former ones is fixed and predetermined, whereas the number of the latter ones has not any bounds. Pledged PLEO delegates are not generally considered superdelegates.

The Republican Party also seats some party officials as delegates without regard to primary or caucus results (see Republican delegate selection), 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.^[2]