"Inside the Beltway" is a phrase used to describe parts of the American political system. It refers to the Capital Beltway (I-495), an interstate highway that encircles Washington, D.C., and is meant to invoke matters that are of importance only within the confines of federal government office buildings.

The term is often pejorative—a dismissive or insulting way to say "it's merely politics, not important," carrying the implication that only people who are paid by the government care. Alternatively, it implies ignorance or indifference with regard to the way things work in what the user of the term regards as the real world. Within the government, however, the phrase can have a positive connotation, meaning the rough equivalent of possessing inside knowledge about American governance and the workings of democracy, or having access to corridors of political power.

The phrase is a form of metonymy, the use of a single characteristic to identify a more complex entity. It is so well known in the U.S. that the mere word "beltway" is used in various combinations for many discussions about national politics, including newspaper columns, television shows, web sites and blogs.

The "Westminster Bubble" is a term for a similar concept in the United Kingdom.