Abstract: Celebrities endorsing e-cigarette brands on social media may exert a strong influence on e-cigarette uptake. Using a between-subject experiment, this study examines the effects of endorser type (celebrities, non-celebrities and products only) in e-cigarette brand Instagram advertisements on e-cigarette attitudes and smoking intentions. Results showed that celebrity endorsers significantly increased positive attitudes towards e-cigarettes and smoking intentions, compared to non-celebrities or products only. Celebrity endorsers also rated significantly higher on trustworthiness, expertise, goodwill and attractiveness, compared to non-celebrities. Additionally, identification, social comparison, health consciousness and social networking site use moderated between endorser type and key dependent measures. Implications for e-cigarette marketing regulation are discussed.