Deviant peer affiliation predicts externalizing behavior in adolescence, but no research explores how having negative or suspicious expectations of others (i.e., distrust) may evoke or buffer against the relationship between deviant peer affiliation and externalizing behavior. The current study used data across two timepoints to investigate the impact of deviant peer affiliation and distrust on externalizing behavior 3 years later and whether race/ethnicity moderated this relationship. The sample consisted of 611 adolescents from the Project on Human Development in Chicago Neighborhoods Study (48% male; Mage = 15.5 years, SD = 1.6; 17% White; 34% Black; 49% Hispanic). Higher levels of distrust buffered against the influence of deviant peer affiliation on externalizing behaviors. Further, this buffering was evident in Black compared to White adolescents. Understanding externalizing behavior warrants considering the intersection between the person and their environment.