This study assessed the smoking practices, risk perception of smoking, and environmental tobacco smoke (ETS) exposure among adolescents in Ciudad Juárez, Mexico. We used a cross-sectional method to examine the smoking practices, risk perception of smoking, and ETS exposure of 6th-grade students (N=506), aged 11-13 years, attending six randomly selected middle schools. Schools were classified by school setting (i.e., public vs. private) and socioeconomic status (SES; i.e., low, middle, or high). The results indicated that 6th-grade students attending a public, low-SES school setting in Ciudad Juárez not only exhibited significantly higher rates of ETS exposure at home and in public places (p<.01) but also were more likely to have tried smoking (p<.01) and to be current smokers (p<.01), and were less likely to support a ban on smoking in public places (p<.01), compared with students who attended a private school or a public, middle- or high-SES school setting. These results provide further evidence that public health interventions to prevent initiation of smoking and to assist in smoking cessation among adolescents and to reduce their ETS exposure at home and in public need to target all school-aged students, especially those attending school in a low-SES settings.