Identity document forgery is the process by which identity documents issued by governing bodies are copied and/or modified by persons not authorized to create such documents or engage in such modifications, for the purpose of deceiving those who would view the documents about the identity or status of the bearer. The term also encompasses the activity of acquiring identity documents from governing bodies by falsifying the required supporting documentation in order to create the desired identity.

Identity documents differ from other credentials in that they are intended only to be usable by the person holding the card. Unlike other credentials, they may be used to restrict the activities of the holder as well as to expand them.

Documents that have been forged in this way include driver's licenses (which historically have been forged or altered as an attempt to conceal the fact that persons desiring to consume alcohol are under the legal drinking age), birth certificates and Social Security cards (likely used in identity theft schemes, or to defraud the government), and passports (used to evade restrictions on entry into a particular country).

Such falsified documents can be used for identity theft, age deception, illegal immigration, and organized crime.

Teslin is used widely in the production of drivers licenses, voter ID cards, and other forms of identification card. Because of its commercial availability, Teslin is also often found used for counterfeit or fake IDs.