Definition of the Criminal Justice System

Updated April 17, 2017

The criminal justice system is composed of legal and social agencies that act to prevent, prosecute or defend, and enforce criminal law, as well as to seek treatment for those in need.


The criminal justice system is made of subsystems including law enforcement agencies, courts, public defenders and prosecutors, probation and parole agencies, custodial institutions, mental health agencies and departments of corrections.


The United States has different federal, military and state criminal justice systems. States have separate criminal justice systems for adult and juvenile offenders.

Criminal Justice Policy

Although they are not usually associated with specific cases, elected officials play a pivotal role in creating the laws that shape the criminal justice system. Media, business and labour organisations also often help shape these laws.

Other Components

In addition to the subsystems, a number of people and agencies play roles within the criminal justice system, including defendants, bail bondsmen, victims and the groups representing them, private defence attorneys and private agencies dealing with offenders.


The various components of the system often have differing objectives, leading to conflicts or unsatisfactory coordination between agencies.

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About the Author

Ann Li has been writing since 2007. She contributes to eHow and international fashion blogs. Li has an Associate of Arts in design and is pursuing a Bachelor of Arts in English from the University of California, Berkeley.