A criminal conspiracy is generally a partnership formed to commit a crime or crimes. A criminal conspiracy exists when two or more persons form an agreement to violate a law that includes criminal penalties, and then take one or more steps designed to accomplish the goal of the conspiracy.

Federal and state statutes make criminal conspiracies illegal for two primary purposes: (1) to help combat the powerful forces created when two or more people collaborate to commit a crime; and (2) to allow criminal prosecutors (state and federal) to prosecute persons who play a role in planning a crime but who are not involved in the physical acts taken to complete the underlying crime.

For example, under federal law, if two or more persons conspire either to commit any offense against the United States, or to defraud the United States, or any agency of the United States in any manner or for any purpose, and one or more of such persons do any act to accomplish the objective of the conspiracy, each of the conspirators may be fined under and imprisoned for up to five years. See 18 U.S.C. §371. And most states have statutes (usually located in the penal or criminal code) that make criminal conspiracies a crime and include significant punishment upon conviction.

In Arizona, criminal conspiracy is defined under Arizona Revised Statutes § 13-1003. A criminal conspiracy occurs when two or more persons come to a mutual understanding to accomplish an illegal objective or to achieve a lawful objective by unlawful means, followed by an overt act in furtherance of the conspiracy. The state of Arizona recognizes the seriousness of collaborative efforts to commit crimes and provides legal mechanisms to prosecute those involved in the planning stages of criminal activity, even if they do not participate in the commission of the crime itself. The punishment for conspiracy in Arizona varies depending on the nature of the crime that the conspirators intended to commit, but it generally carries a penalty that is one class lower than the penalty for the actual offense planned. For instance, if the target offense is a Class 2 felony, the conspiracy to commit that offense would be a Class 3 felony. This approach aligns with the dual purposes of conspiracy laws: to dismantle the collective power of individuals working together to commit crimes and to hold accountable those who contribute to criminal endeavors through planning and agreement, regardless of their involvement in the crime's execution.