In the common law legal system, an expungement or expunction proceeding, is a type of lawsuit in which an individual who has been arrested for or convicted of a crime seeks that the records of that earlier process be sealed or destroyed, making the records nonexistent or unavailable to the general public. If successful, the records are said to be "expunged". Black's Law Dictionary defines "expungement of record" as the "Process by which record of criminal conviction is destroyed or sealed from the state or Federal repository." While expungement deals with an underlying criminal record, it is a civil action in which the subject is the petitioner or plaintiff asking a court to declare that the records be expunged.

A very real distinction exists between an expungement and a pardon. When an expungement is granted, the person whose record is expunged may, for most purposes, treat the event as if it never occurred. A pardon (also called "executive clemency") does not "erase" the event; rather, it constitutes forgiveness. In the United States, an expungement can be granted only by a judge, while a pardon can be granted only by the President of the United States for federal offenses, and the state governor, certain other state executive officers, or the State Board of Pardons and Paroles (varies from state to state) for state offenses.

Each jurisdiction whose law allows expungement has its own definitions of expungement proceedings. Generally, expungement is the process to "remove from general review" the records pertaining to a case. In many jurisdictions, however, the records may not completely "disappear" and may still be available to law enforcement, to sentencing judges on subsequent offenses, and to corrections facilities to which the individual may be sentenced on subsequent convictions.

Criminal records in each state of Australia are covered by state law. In New South Wales, the relevant legislation is the Criminal Records Act 1991. Under the Act, an offender's criminal record may become spent if they do not re-offend for a period of 10 years. Offenses resulting in a prison term of more than six months will not become spent. Additionally, for certain employment occupations (e.g. education or child services), a "full disclosure" check is required, and spent convictions are still visible.

In June 2018, the Parliament of Canada enacted the Expungement of Historically Unjust Convictions Act, in order to further promote LGBT rights and cancel out certain criminal laws that were once effective. Under the Act, the Parole Board of Canada must order expungement of a conviction in respect of an offence that relates to acts of gross indecency, anal intercourse or buggery, as defined prior to 1969 and later on under the now repealed section 159 of the Criminal Code, if the activity for which the person was convicted was between persons of the same sex, the persons other than the person who was convicted had given their consent to participate in the activity, and the persons who participated in the activity were 16 years of age or older at the time the activity occurred.

When notified of the expungement order, the RCMP and any federal department or agency must destroy or remove any judicial record of the conviction to which the expungement order relates that is in its repositories or systems. Provincial and municipal police forces and courts must also be notified of the expungement order. The person convicted of the offence is then deemed never to have been convicted of that offence.

The European Court of Human Rights has ruled that a person has a right to have their convictions erased from all records after the passing of certain time. As of September 2020, there is currently a case pending with the Court which aims at the ruling that permanent keeping of the records is excessive.

Expungement in New Zealand is regulated by the Criminal Records (Clean Slate) Act 2004.