Burglary is a crime related to theft. The original common law definition of burglary consisted of breaking and entering the dwelling of another during the night with the intention to commit a felony therein.

Laws in many jurisdictions impose much harsher penalties for burglaries committed or attempted at night, or upon an occupied residence. Burglary laws in some jurisdictions also encompass certain types of shoplifting.

United States

In the United States burglary is generally a felony and involves trespassing, or entering a building with intent to commit any crime, not necessarily a felony or theft. Thus, a conviction for burglary may qualify as a conviction under a three strikes law or habitual criminal statute, even though only something of low value or nothing at all was stolen. As with all legal definitions in the US, the foregoing description may not be applicable in every jurisdiction since there are 51 separate criminal codes in force.

The state of Massachusetts is somewhat unique in that it does not formally use the term "burglary;" instead, the acts of breaking and entering and any theft that occurs coincident with such entry are treated as separate offenses, with the former being officially denoted "breaking and entering in the nighttime (or daytime, as applicable) with intent to commit a felony (or misdemeanor, as applicable)," and the latter "(grand or petit) larceny from a building," if any property was indeed stolen. Thus if the perpetrator's intended act after entering the burglarized premises was not a felony, the result can be two different misdemeanor charges rather than a felony count.

Many other U.S. states treat burglary as a more serious crime when it occurs at night; California, for example, prosecutes nighttime burglary as "burglary in the first degree" and daytime burglary as "burglary in the second degree," under most circumstances.

England and Wales

In England and Wales, burglary is dealt with in the Theft Act 1968 under section 9. Subsection (1)(a) says that any person who enters any building, part of a building, inhabited vehicle or vessel with the intent to steal, cause grievous bodily harm, criminally damage or commit rape will be guilty of the offence of burglary. Subsection (1)(b) provides for a different type of burglary, where any person having entered any building, part of a building, inhabited vehicle or vessel commits a theft or inflicts gross bodily harm. It is a necessary component, however, that in either eventuality that the perpetrator must be trespassing at the time of the offence.

There is also an offence of Aggravated Burglary under Section 10 of the Act. A burglary becomes aggravated when a burglar has with him at the time a weapon of offence, imitation firearm, firearm or explosive. (There is no requirement that any of these items are used in the commission of the offence merely that they are in the possession of the burglar at the time). Maximum sentences for Section 9 offences are 10 years for a non-dwelling and 14 years for a dwelling. Section 10 offences carry a maximum of life imprisonment. Burglary is triable either summarily (before a Magistrate) or on indictment in the Crown Court.