Adjudicative competence is the requirement that defendants are able to participate meaningfully in their defence. The Dusky standard ( Dusky v. United States, 362 U.S. 402, 1960) requires that defendants possess the capacity to understand and appreciate the nature of the legal proceedings, as well as the capacity to assist counsel. In criminal court, adults are generally adjudicated incompetent due to major mental illness and/or cognitive impairment. Concern about the adjudicative competence of juvenile court defendants has increased in recent decades and there is a clear trend in the United States toward the development of juvenile-specific competency laws. These laws and the practices of evaluators who examine the issue must address unique aspects that arise in juvenile competency questions. A wider array of mental health problems and cognitive limitations may lead youth to lack capacities required to be competent. This is largely due to functional weaknesses associated with normal developmental immaturity. A finding of incompetence often results in efforts to alleviate or remediate the impediments to competence. Educational and/or skill-based interventions are the most common approach to competency remediation with juveniles. However, remediation is challenged to address deficits associated with developmental immaturity. How to best serve youth who are incompetent due to immaturity, as well as youth in general who, for various reasons, are not responsive to remediation efforts and remain incompetent, is a challenge that will need to be addressed by policymakers in the future.