A Constituency Labour Party is an organization of members of the Labour Party (UK) who live in a particular constituency. The CLP selects the local Labour Party candidate for a national parliamentary election (general election) (although the National Executive Committee controversially has powers to overrule this decision in certain circumstances). The CLPs consist primarily of individual Labour Party members (those who have joined the Labour Party of their own accord), but meetings may also be attended by members of affiliated organizations (for example, local trade unions or co-operative societies which have affiliated to the CLP).

A CLP's two main decision-making bodies are normally its General Committee (or General Management Committee), referred to in Labour circles as the GC, and its Executive Committee. Some CLPs have merged the GC and EC into a single committee. In many cases, the members of the GC and EC are the same people in any case. A few CLPs have abolished the GC and organized all-member meetings to take decisions. Others follow the traditional system, where the GC and EC retain the decision-making powers, and the members of those committees are elected by branch Labour parties (BLPs - local Labour parties, often organized at ward level) and (a smaller number) by affiliates.

The main officials in a CLP are ordinarily the Secretary, Chair, and Treasurer.

For much of Labour history, including during the 1980s, the CLPs were perceived as the most leftwing faction in the Labour Party, with the unions actually being a more moderate or pragmatic force.