Adolescents' sleep duration was examined as a moderator of the association between perceived discrimination and internalizing (anxiety, depression) and externalizing symptoms. Participants were 252 adolescents (mean: 15.79 years; 66% European American, 34% African American) who reported on their perceived discrimination (racial and general) and adjustment. Sleep duration was measured using actigraphy. Moderation effects were evident. The lowest levels of internalizing symptoms were observed for adolescents with longer sleep duration in conjunction with lower levels of perceived racial discrimination. Further, general perceived discrimination was associated more strongly with externalizing behaviours for youth with shorter versus longer sleep. Findings highlight the importance of sleep as a bioregulatory system that can ameliorate or exacerbate the effects of discrimination on youths' adjustment.