This study established the importance of differential associations in the transition to juvenile daily smoking while examining whether these associations exerted sex-specific influences. Consistent with past studies, parental attitudes and behaviors have substantial impacts on juvenile smoking. Close peers who hold pro-smoking definitions and provide smoking models to imitate contribute the most substantial risk. Girls are particularly susceptible to the smoking patterns of a steady romantic partner, feeling more pressure to engage in deviant behaviors. Suggestions and recommendations are made for juvenile antismoking and smoking cessation programs. The existing body of research on juvenile smoking is extensive however; the majority of studies examine only initiation or experimentation. This study examined how four key differential associations affected smoking behaviors of juveniles: parents, siblings, best friends, and boyfriends or girlfriends and focused on their role in predicting daily smoking. It was argued that such groups would have sex-specific influences, with girls and boys being more susceptible to same-sex family models. Data were drawn from surveys conducted with 7th through 12th grade students in Tucson, AZ in 1996 and 2000. A total of 7,725 students were surveyed in 1996 and 7,404 students in 2000. Tables, references