Patients with traumatic brain injury (TBI), especially those with personality change or who manifest difficulties in consciousness, judgment, mood regulation, memory, orientation, insight, and impulse control, can raise complex legal and ethical problems (Warriner and Velikonjad 2006). TBI creates situations requiring the patient, and thus the clinician, to interface with multiple systems. People with TBI frequently are involved in criminal, civil, or administrative legal situations. They may be involved as disability claimants, witnesses, victims, plaintiffs, criminal defendants, respondents, or petitioners, in a wide variety of circumstances. TBI has become associated with the wars in Afghanistan and Iraq, challenging systems of health care delivery, rehabilitation, and compensation. Readers of this chapter may find themselves working with people with TBI as treatment providers or as expert witnesses commenting on various types of competencies, petitioning for guardianship or conservatorship, supporting accommodations and services under the Individuals With Disabilities Education Act (1997) or the Americans With Disabilities Act (1990), testifying on the effects of the TBI on the person's life or predictions of future behaviors, or providing estimations of whether the injury's effects are being overstated, among many possible roles. TBIs, when initially seen, may require a report to authorities under a mandated reporter statute. Injuries that result in a persistent vegetative state may require ethical consultation if further care is felt to be futile and the substitute decision maker is requesting termination of further lifesaving or maintenance interventions. The basic legal and ethical concepts discussed in this chapter are applicable to other forms of brain injury or disorders.