Perjury is the criminal offense of making a false statement under oath—verbally or in writing—that the witness knows to be false and that is material to the proceeding in which the statement is made. And suborning perjury or subornation of perjury is the criminal offense of procuring the perjury of another person.

Perjury is a criminal offense under both state and federal laws and may be prosecuted as a misdemeanor or as a felony offense, depending on the state or federal jurisdiction, and whether there are any aggravating factors that increase the seriousness of the crime. Perjury laws are located in state statutes—often in the penal or criminal code—and the federal perjury law is located in the United States Code at 18 U.S.C. §1621.

In Kentucky, perjury is considered a serious criminal offense. It is defined as intentionally making a false statement, under oath, on a material matter during a legal proceeding, knowing the statement to be false. This applies to both verbal and written statements. Kentucky law classifies perjury as a Class D felony, which can result in penalties including imprisonment and fines. Subornation of perjury, which involves persuading or inducing another person to commit perjury, is also a criminal offense in Kentucky and is subject to similar penalties as perjury itself. These state laws are found in the Kentucky Revised Statutes (KRS), specifically KRS 523.020 for perjury and KRS 523.030 for subornation of perjury. Additionally, federal law under 18 U.S.C. § 1621 also prohibits perjury and subornation of perjury, and these offenses can be prosecuted in federal court if the false statement is made in relation to a federal proceeding or involves a federal agency.