We performed a secondary analysis of Adolescent Health Risk Behavior Survey data (N=937), examining associations between lifetime alcohol and marijuana use with intrapersonal (i.e., risk perceptions) and interpersonal (e.g., peer approval and behavior) factors. Multinomial and binary logistic regression analyses contend students reporting lifetime alcohol use--compared to students who had never used alcohol or marijuana--perceived lower alcohol risk (p < 0.001), higher friend drinking approval (p < 0.001), and greater friend drinking (p = 0.003). Using both alcohol and marijuana in one's life was associated with being in public schools (p = 0.010), higher grade levels (p = 0.001), lower perceived alcohol (p = 0.011) and marijuana use risk (p = 0.003), higher friend approval of alcohol (p < 0.001) and marijuana use (p < 0.001), and believed more friends used alcohol (p < 0.001). Compared to lifetime alcohol only, perceived friend academic performance decreased the risk of lifetime alcohol and marijuana use (p = 0.043). Findings are beneficial to school nurses with students experiencing effects associated with substance use.