Burglary is generally the unlawful entry of a building or structure to commit a felony criminal offense (crime), theft, or assault. The definition of burglary varies from state to state (and in the federal system), and some states have different degrees of severity of the burglary offense—depending on the nature of the unlawful entry (type of building or structure), the intended purpose, and the illegal action taken by the defendant once inside the building or structure. In some states, breaking into an automobile, a coin-operated machine, or an ATM (automated teller machine) with the intent to commit a theft may also constitute the crime of burglary.

In Arizona, burglary is defined under Arizona Revised Statutes (ARS) and is categorized into different degrees based on the severity of the offense. First-degree burglary (ARS 13-1508) involves the unlawful entry into or remaining in a residential or non-residential structure or a fenced residential or commercial yard with the intent to commit theft or any felony, while the offender or an accomplice is knowingly in possession of explosives, a deadly weapon, or a dangerous instrument. Second-degree burglary (ARS 13-1507) pertains to similar unlawful entry or remaining with intent to commit theft or a felony in a residential structure, but without the aggravating factors of weapons or explosives. Third-degree burglary (ARS 13-1506) applies to the unlawful entry into or remaining in a non-residential structure or a fenced commercial yard, or the unlawful entry into any part of a motor vehicle by means of a manipulative key or master key, with the intent to commit theft or a felony. The penalties for burglary in Arizona vary depending on the degree of the offense, with first-degree burglary carrying the most severe penalties, including potential prison time.