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 Alabama, burglary is defined under the Alabama Criminal Code (Section 13A-7-5 to 13A-7-7) and is categorized into three degrees. First-degree burglary (Section 13A-7-5) is the most serious form, involving the unlawful entry into an occupied dwelling with the intent to commit a crime inside, and it becomes especially severe if the perpetrator is armed or causes physical injury. Second-degree burglary (Section 13A-7-6) involves similar elements but pertains to unoccupied dwellings and buildings. Third-degree burglary (Section 13A-7-7) covers the unlawful entry into a building with the intent to commit a theft or felony, regardless of whether it is occupied. Alabama law also recognizes burglary of a vehicle as a separate offense, known as 'unlawful breaking and entering a vehicle' (Section 13A-8-11), which is a Class C felony if the intent is to commit a theft or felony inside the vehicle. The specific circumstances of the unlawful entry, such as the time of day and whether the structure is a dwelling or another type of building, can affect the degree of the charge and the potential penalties upon conviction.