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 Missouri, perjury is defined as knowingly making a false statement under oath or affirmation in a proceeding or in any other matter where by law the statement is required or authorized to be made under oath. This includes both verbal and written statements. Missouri statutes classify perjury as a Class D felony, which can result in significant penalties including imprisonment and fines. Suborning perjury, or persuading another person to commit perjury, is also a criminal offense in Missouri and is subject to similar penalties as perjury itself. At the federal level, perjury is governed by 18 U.S.C. § 1621, which also makes it a crime to willfully make false statements under oath in federal proceedings, with penalties that can include fines and imprisonment. The severity of the punishment for perjury or subornation of perjury can vary based on the circumstances and the impact of the false statement on the proceedings.