A joint committee is a committee that draws its members from more than one organization. In countries with a bicameral legislature, the term is most frequently used in politics to describe a committee with members from both houses of the legislature. Although the term "joint committee" most often refers to a government committee, joint committees also can be found when non-government organizations are working together.

In the United States Congress, joint committees are bodies with members from both the House of Representatives and the Senate. There are four standing joint committees in the U.S. Congress: the Joint Committee on Taxation, the Joint Committee on the Library, the Joint Committee on Printing and the Joint Economic Committee. The position of chairman for these committees rotates between the Committee's most senior Senator and its most senior Representative.

Special joint committees can be formed temporarily for more specific subjects. Past examples of this include the Joint Committeemen on Atomic Energy and the Joint Committee on Reconstruction. The scope of these committees can vary enormously, ranging from the United States Congress Joint Committee on the Conduct of the War, which helped oversee the waging of the Civil War, to committees for very narrow issues such as the Joint Committee on Arrangements for the Bicentennial and the Joint Committee on the Ford's Theater Disaster. In addition, the Joint Congressional Committee on Inaugural Ceremonies is formed once every four years to plan the inauguration ceremony of the President of the United States, along with associated events.

Parliamentary democracies using the Westminster system of government also have joint select committees with members of both Houses of Parliament to address particular subjects. For example, in the United Kingdom, there are two standing joint committees that meet regularly, the Committee on Human Rights and the Committee on Statutory Instruments. Joint committees also can be formed temporarily for specific issues or bills. The United Kingdom also uses the term “joint committee” to refer to local delegated government bodies that oversee distribution of government services in their areas and consult with local councils.

Joint committees often appear in international relations and international organizations. International groups such as the North Atlantic Treaty Organization (NATO) often form joint committees for important issues. For instance, the Joint Committee on Proliferation is a NATO advisory body with representatives of all NATO member states that issues reports on the proliferation of nuclear, biological and chemical weapons. Trade agreements between nations often are written by joint committees with members from each country or from international bodies such as the European Free Trade Association.

The term “joint committee” also appears in nongovernmental contexts. The Joint Committee on Testing Practices is one example. It is a cooperative effort by three groups in the U.S.: the American Psychological Association, the American Educational Research Association and the National Council on Measurement in Education.