Behavioral self-regulation (BSR), defined herein as the degree to which one can control one's own activity and reactivity to environmental stimuli, has been posited to be salient to the onset of adolescent substance abuse. The goal of this study was to clarify particular family and peer correlates of BSR in at-risk sons. Subjects were 10-through 12-year-old sons of substance-abusing fathers (high-average risk [HAR]; n = 176) and normal controls (low-average risk [LAR]; n = 199). A BSR latent trait was developed using multiple measures and multiple informants. Analyses included separate hierarchical linear regressions for HAR and LAR groups. In the hierarchical linear model for HAR sons, family dysfunction and deviant peer affiliation were significantly associated with BSR, whereas for LAR sons, only peer affiliation was significantly associated with BSR. The above family and peer correlates differed in proportions of variance explained for BSR in HAR and LAR sons. These findings extend previous studies by showing that, in a hierarchical linear model, BSR in HAR sons is associated with specific interpersonal, family, and peer factors. These findings suggest that empirical, theory-guided interventions to prevent worsening of BSR in HAR boys should address specific interpersonal, family, and peer factors.