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 Kansas, perjury is defined as intentionally making a false material statement under oath or affirmation in any official proceeding or in any written document legally requiring such a statement. It is considered a severity level 9, nonperson felony under Kansas law, as outlined in the Kansas Statutes Annotated (K.S.A.) 21-5904. Subornation of perjury, which involves persuading or inducing another person to commit perjury, is also a criminal offense. The penalties for perjury can include fines, imprisonment, or both, depending on the circumstances of the case and the discretion of the court. At the federal level, perjury is governed by 18 U.S.C. §1621, which makes it illegal to willfully and contrary to an oath state or subscribe to any material matter which the individual does not believe to be true. Federal perjury is punishable by fines and/or imprisonment. Both state and federal laws treat perjury seriously due to its potential to undermine the judicial system.