In most states persons accused of violating the law before they are 18 years of age are under the jurisdiction of the juvenile courts, and persons accused of violating the law when they are 18 years of age or older are under the jurisdiction of the criminal courts. Some states begin prosecuting persons as adults in the criminal court system when they are 17 years of age, and some states begin prosecuting persons as adults in the criminal court system when they are 16 years of age.

But all states have transfer laws that permit or require criminal prosecution of some young offenders—even though they are still of juvenile age, as defined by the state’s laws. Transfer laws vary from state to state, but generally fall within three categories: (1) judicial waiver laws that allow juvenile courts to waive jurisdiction on a case-by-case basis; (2) prosecutorial discretion or concurrent jurisdiction laws that define a class of cases that may be brought in juvenile court or in criminal court—usually at the discretion of the prosecutor; and (3) statutory exclusion laws that grant criminal courts exclusive jurisdiction over certain classes of cases involving juvenile-age offenders.

The laws that govern when a person of juvenile age may be prosecuted as an adult in the criminal court system are generally located in a state’s statutes.

In Texas, individuals who are 17 years of age or older are automatically prosecuted as adults in the criminal court system. For those under 17, Texas employs a system of transfer laws that can move juvenile cases to adult court under certain circumstances. These transfer laws include judicial waiver, prosecutorial discretion, and statutory exclusion. Judicial waiver allows a juvenile court judge to transfer a case to adult court if the judge believes the juvenile should be tried as an adult, typically after considering factors such as the seriousness of the offense, the juvenile's maturity, and their criminal history. Prosecutorial discretion gives prosecutors the authority to file certain cases either in juvenile or adult court, often depending on the nature of the offense and the age of the offender. Statutory exclusion means that certain offenses committed by juveniles are automatically excluded from juvenile court jurisdiction and must be tried in adult court. These laws are codified in the Texas Family Code and the Texas Penal Code.