Race/ethnic disparities in utilization of children's mental health care have been well documented and are particularly concerning given the long-term risks of untreated mental health problems (Institute of Medicine, 2003; Kessler et al. Am J Psychiatry 152:10026-1032. Research investigating the higher rates of unmet need among race/ethnic minority youths has focused primarily on policy, fiscal, and individual child or family factors that can influence service access and use. Alternatively, this study examines provider behavior as a potential influence on race/ethnic disparities in mental health care. The goal of the study was to examine whether patient (family) race/ethnicity influences physician diagnostic and treatment decision-making for childhood disruptive behavior problems. The study utilized an internet-based video vignette with corresponding survey of 371 randomly selected physicians from across the USA representing specialties likely to treat these patients (pediatricians, family physicians, general and child psychiatrists). Participants viewed a video vignette in which only race/ethnicity of the mother randomly varied (nonHispanic White, Hispanic, and African American) and then responded to questions about diagnosis and recommended treatments. Physicians assigned diagnoses such as oppositional defiant disorder (48 %) and attention deficit disorder (63 %) to the child, but there were no differences in diagnosis based on race/ethnicity. The majority of respondents recommended psychosocial treatment (98 %) and/or psychoactive medication treatment (60 %), but there were no significant differences based on race/ethnicity. Thus, in this study using mock patient stimuli and controlling for other factors, such as insurance coverage, we did not find major differences in physician diagnostic or treatment decision-making based on patient race/ethnicity.