Acculturation increases the risk of smoking among Hispanic and Asian American adolescents, but the underlying mechanisms are not understood. This study examined associations between English language use and smoking among 4,167 Hispanic and 2,836 Asian American adolescents in California. Potential mediators were assessed, including access to cigarettes, perceived consequences, friends' smoking, cigarette offers, refusal self-efficacy, and prevalence estimates of peer smoking. English language use was associated with increased risk of lifetime smoking in both groups. This association became nonsignificant after access, perceived consequences, friends' smoking, and offers were controlled for. The acculturation process (as indicated by English language use) may be associated with smoking-related psychosocial variables, which may lead to an increased risk of experimentation with smoking.