Police ranks are a system of hierarchical relationships in police organisations. The rank system defines authority and responsibility in a police organisation, and affects the culture within the police force. Usually, uniforms denote the bearer's rank by particular insignia affixed to the uniforms.

Law enforcement in the United Kingdom is organised separately in each of the legal systems of the United Kingdom: England and Wales, Scotland, and Northern Ireland. Most law enforcement duties are carried out by those who hold the office of police constable of a territorial police force.