A habitual offender, also known as a repeat offender or career criminal, is a person who has been convicted of a crime and has previously been convicted of other crimes. The nature, scope, and type of habitual offender statutes vary, but generally, they apply when a person has been convicted twice for various crimes. Some codes may differentiate between classes of crimes, and the length of time between convictions. Usually, the sentence is greatly enhanced, and in some circumstances, it may be substantially more than the maximum sentence for the crime. Habitual offender laws may provide for mandatory sentencing, in which a minimum sentence must be imposed, or may allow judicial discretion in allowing the court to determine a proper sentence.

Habitual offender laws aim to decrease the rate of repeated criminal activity by increasing the severity of punishment and intensifying the requirements for probation or parole. The penalties for habitual offenders may include longer prison sentences, supervised probation, higher fines, revocation or suspension of licenses, and the loss of certain civil liberties. The availability of habitual-offender laws may unfairly enhance the powers of prosecutors, who can entice petty offenders to plead guilty by threatening to charge them with.

In some states, a habitual offender law may increase the severity of punishment that a repeat offender receives. It may also intensify the number of requirements that a convicted offender must satisfy to complete their probation or parole period or alter the type of crime that they are charged with. A habitual offender law may also focus on a specific type of crime. For instance, if an individual commits and is convicted of enough prior incidents of misdemeanor petty theft, then the state statute may provide that their next instance of misdemeanor petty theft will constitute a felony crime.