Objective: To examine how norm appeals and guilt influence smokers' behavioural intention. Design: Quasi-experimental design. Setting: South Korea. Method: Two hundred and fifty-five male smokers were randomly assigned to descriptive, injunctive, or subjective anti-smoking norm messages. After they viewed the norm messages, their norm perceptions, guilt and behavioural intention were measured. Results: The study revealed several findings: (1) injunctive norm perceptions significantly affected behavioural intention; (2) descriptive norm perceptions had a non-significant impact; (3) subjective norm perceptions had an unexpected impact on behavioural intention; (4) guilt arousal strongly and directly affected behavioural intention in all three conditions; and (5) guilt arousal did not mediate the relationship between norm perceptions and guilt. Conclusion: Injunctive norms messages that smoking in the presence of others is an unacceptable behaviour in society could persuade smokers to alter their behaviours. In addition, our study suggests substantial potentials of guilt in smokers' behaviour change.