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 Pennsylvania, perjury is defined as intentionally making a false statement under oath in any official proceeding, knowing the statement to be false. This is outlined in the Pennsylvania Consolidated Statutes, Title 18, Section 4902. Perjury in Pennsylvania is considered a felony of the third degree, which can result in serious penalties including imprisonment and fines. Subornation of perjury, which involves persuading or inducing another person to commit perjury, is also a criminal offense under Pennsylvania law. The penalties for subornation of perjury are comparable to those for perjury itself. At the federal level, perjury is governed by 18 U.S.C. § 1621, which similarly criminalizes the act of willfully making false statements under oath in federal proceedings, with penalties that can include fines and imprisonment. Both state and federal laws treat perjury and subornation of perjury as serious offenses due to their potential to undermine the integrity of the judicial system.