Criminal procedure is the process related to the investigation, arrest, charging, and conviction or acquittal of a criminal defendant. Much of criminal procedure is comprised of processes and rules through which the government (state, federal, or municipal) enforces substantive criminal law and through which a criminal defendant’s Constitutional and other rights are protected.

The law of criminal procedure is primarily located in the applicable state or federal rules of criminal procedure and state and federal court opinions interpreting and applying Constitutional and other legal rights.

In Tennessee, criminal procedure is governed by a combination of state statutes, the Tennessee Rules of Criminal Procedure, and federal laws, including constitutional protections afforded to defendants. These procedures outline the steps from the initial investigation of a crime to the arrest, charging, and eventual trial of a suspect. They ensure that a defendant's rights, such as the right to a fair trial, the right to counsel, and protection against self-incrimination and unreasonable searches and seizures, are upheld throughout the criminal justice process. The Fourth, Fifth, Sixth, and Fourteenth Amendments to the U.S. Constitution play a crucial role in criminal procedure, influencing state practices and providing a framework for the protection of individual rights against improper government action. Tennessee's rules and statutes must comply with these constitutional standards, and both state and federal court opinions interpret and apply these rules to ensure that criminal proceedings are conducted fairly and justly.