Burglary, in English common law, breaking into and entering the dwelling of another person at night with the intention of committing a felony, or serious crime. In the United States most states have broadened this definition so that burglary may be committed by day and by breaking into buildings other than residences. Although it is usually thought of as entering a building with the intent to steal, burglary is committed whenever a person enters, or tries to enter, a building in order to commit any felony, including murder or kidnapping. In this respect, burglary differs from larceny and robbery, which always involve the unlawful taking of property.

In common law, to be guilty of burglary a person must forcibly break into the building in which he intends to commit a crime. The force used, however, may be as slight as that required for opening an unlocked window or a partially open door. Many modern statutes do not require that force be used; mere entry is sufficient to commit burglary. Burglary is committed even when the attempted entry fails, or if the crime for which the building is entered is not carried out.