In a sample of 711 ethnically diverse adolescents, the observed interpersonal dynamics of dyadic adolescent friendship interactions were coded to predict early adulthood tobacco, alcohol, and marijuana use. Deviant discussion content within the interactions was coded along with dyadic coregulation (i.e., interpersonal coordination, attention synchrony). Structural equation modeling revealed that, as expected, deviant content in adolescent interactions at age 16-17 years was strongly predictive of problematic use of tobacco, alcohol, and marijuana at ages 22 and 23. Although dyadic coregulation was not directly predictive of early adulthood substance use, it did moderate the impact of deviant talk within the dyad on future alcohol and marijuana use. For these substances, high levels of dyadic coregulation increased the risk associated with high levels of deviant talk for problematic use in early adulthood. Results held when comparing across genders and across ethnic groups. The results suggest that these interpersonal dynamics are associated with developmental trajectories of risk for or resilience to peer influence processes.