In response to the need for effective tobacco prevention programmes in the Islamic Republic of Iran, the present study sought to determine the major risk factors for initiation of smoking by adolescents. A content analysis with a qualitative approach was conducted through 22 in-depth interviews, 2 focus groups (4 and 6 participants in each group) and 30 narratives. The following 3 themes emerged from the analysis as risk factors for initiating smoking by adolescents: personal factors, social factors and beliefs about smoking. Based on these findings, it is recommended that prevention activities should be embedded in a comprehensive approach which aims to change the smoking and parenting behaviour of parents and teachers, and at creating non-smoking policies in schools and other places where young people congregate.