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 Colorado, perjury is addressed under state statutes, specifically in the Colorado Revised Statutes (C.R.S.). Perjury is considered a serious offense and is classified into two degrees. First-degree perjury, as defined in C.R.S. 18-8-502, is a class 4 felony and occurs when an individual makes a materially false statement, which they do not believe to be true, under oath in an official proceeding. Second-degree perjury, under C.R.S. 18-8-503, is a class 1 misdemeanor and involves making a materially false statement, which the individual does not believe to be true, under oath, but outside the context of an official proceeding. Suborning perjury, which is persuading another person to commit perjury, is also a criminal offense under Colorado law and is treated with similar severity to perjury itself. At the federal level, perjury is governed by 18 U.S.C. §1621, which makes it a crime to willfully make false statements under oath in federal proceedings, and this can be prosecuted as a felony. The specific classification and penalties for perjury can vary based on the circumstances and the jurisdiction in which the offense occurs.