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.

A defendant generally commits the offense of burglary of a building or habitation (1) by entering a private habitation or any part of a building that was not open to the public, (2) without the consent of the owner, and (3) with the intent to commit a felony, theft, or assault.

A defendant may also commit the offense of burglary of a building or habitation by entering with consent, but remaining hidden with the intent to commit a felony, theft, or assault—or entering with consent and attempting to commit a felony, theft, or assault, or actually committing a felony, theft, or assault.

Some states make a distinction between burglary of a habitation (a place used for overnight accommodations) and burglary of a building that is not a habitation (home). Burglary of a habitation is usually treated as a more serious offense with greater penalties.

In Kentucky, burglary is defined under Kentucky Revised Statutes (KRS) and is classified into different degrees based on the severity of the offense. Burglary in the first degree (KRS 511.020) occurs when a person knowingly enters or remains unlawfully in a dwelling with the intent to commit a crime therein, and when, in effecting entry or while in the dwelling or in immediate flight therefrom, he or she is armed with explosives or a deadly weapon, or causes physical injury to any person who is not a participant in the crime, or uses or threatens the use of a dangerous instrument against any person who is not a participant in the crime. Burglary in the second degree (KRS 511.030) involves unlawfully entering or remaining in a building (other than a dwelling) with intent to commit a crime, and is considered a Class C felony. Burglary in the third degree (KRS 511.040) is the unlawful entry into a building with intent to commit a crime, but without the aggravating factors present in the first and second degrees, and is a Class D felony. Kentucky law also recognizes the offense of possession of burglar's tools (KRS 511.050), which involves possessing any tool with the intent to use it or knowing that someone intends to use it to commit burglary or theft. The distinction between burglary of a habitation and other buildings is significant in Kentucky, with burglary of a habitation being treated more seriously and carrying greater penalties.