With the increase in juvenile crime, the number of juveniles being charged in criminal court, and the increased emphasis on punishment, juvenile competency to stand trial has received a great deal of attention. However, due to the structure of juvenile courts, competency to stand trial has only recently become an issue of importance. In this study, differences in adjudicative competency among juveniles who were either awaiting adjudication or members of an age-matched control group were assessed using the MacArthur Competence Assessment Tool-Criminal Adjudication (MacCAT-CA). The MacCAT-CA contains three scales: Understanding, Reasoning, and Appreciation. The study compared juveniles of varying ages who were facing adjudication with a control group of age-matched adolescents recruited from the community, in hopes to better understand the relationship between developmental stages and competency and to indicate if a difference exists between the abilities of offenders and nonoffenders. Participants in the study included 110 adolescents (60 boys and 50 girls) between 10 and 17 years of age. Sixty-four percent of the participants were awaiting adjudication in juvenile court. There were 40 study participants or 36 percent of the participants who had not been involved in adjudication. As hypothesized, juveniles’ scores on the MacCAT-CA became more like those of adults as age increased. The overall findings of the study reinforce previous research indicating that adolescents below the ages of 15 to 16 years cannot be assumed to be competent, as are adults, and that cognitive maturation and intellectual ability are related to competency. Tables and references