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 Maryland, criminal procedure encompasses the rules and guidelines that govern the handling of criminal cases from the initial investigation to the arrest, charging, trial, and resolution of the case, whether by conviction, acquittal, or other means. These procedures are designed to ensure the enforcement of criminal laws while protecting the constitutional rights of the accused, such as the right to a fair trial, the right to counsel, and protection against self-incrimination and unreasonable searches and seizures. Maryland's criminal procedure is codified in the Maryland Rules of Procedure and is interpreted by state court opinions. Additionally, federal rules and constitutional protections apply to criminal proceedings in Maryland, particularly through the Fourth, Fifth, Sixth, and Fourteenth Amendments to the U.S. Constitution. These federal standards provide a baseline of rights that states cannot infringe upon, although they may offer additional protections. It is important for individuals involved in the criminal justice system to consult with an attorney who is knowledgeable about both state and federal criminal procedures to navigate the complexities of the legal process.