Expulsion from Congress is the most serious form of disciplinary action that can be taken against a member of Congress. The United States Constitution (Article I, Section 5, Clause 2) provides that "Each House . Expulsion is considered a disciplinary matter and a matter of self-protection of the integrity of the institution and its proceedings. The processes for expulsion differ somewhat between the House of Representatives and the Senate.

In the entire history of the United States Congress, 20 Members have been expelled: 15 from the Senate and five from the House of Representatives. Seventeen of these 20 were expelled for supporting the Confederate States in 1861 and 1862. Censure, a less severe form of disciplinary action, is an official sanction of a member. It does not remove a member from office.

Expulsion is a removal of a member from Congress by a two-thirds vote of the House or Senate. Expulsion from the House of Representatives carries with it no further "automatic" penalties or disabilities beyond removal from Congress. Although the constitutions of some states provide that members expelled from their state legislatures are ineligible to be reelected to that legislature, no such disability was included in the United States Constitution for Members of Congress.