Research has established that youth of color are overrepresented throughout juvenile justice processing. The causes of this overrepresentation are not clear, however. Some analysts attribute it to “differential involvement,” i.e., higher rates of offending by minorities compared with Whites. Others attribute the overrepresentation to “differential selection,” i.e., the tendency of justice-system decisionmakers to view minority youth as more delinquency prone than White youth. Others believe minority overrepresentation results from a combination of these two factors. These unanswered questions about causes have impeded the design of effective interventions for addressing racial/ethnic disparity in juvenile justice processing. The author recommends research on how each of the two hypotheses can explain both the fact of minority overrepresentation in the juvenile justice system and how best to address it. Research is especially needed in analyzing the first stage of the justice system’s processing of juveniles, i.e., police contacts. Police make the first decision about which youth are referred to juvenile justice processing. Police are afforded more decisionmaking latitude than any other formal agent of social control; however, researchers have paid little attention to factors involved in the initiation of police contacts with youth and the decision by officers to refer youth to formal intake. Researchers should also examine the consequences of disproportionate minority representation in the juvenile justice system, such as poor outcomes in education, employment, and family life. Research should also update justice system data systems and repositories, which have not tracked changes in U.S. demographic and immigration patterns. 1 figure and 70 notes