A questionnaire on smoking behaviour and certain family and school factors was administered to over 700 11–12 year olds attending nine schools in the Western Area of Northern Ireland. The results showed that over 7% of the children smoked regularly and a further 6% smoked occasionally. The children's smoking behaviour was related to the smoking behaviour and attitude to children smoking of their parents, siblings and friends. There was a sex linking in these relationships. Smoking behaviour was not related to type of school, location of school or whether the school included anti-smoking education in the curriculum. But boys who reported trouble at school and girls who thought their teachers had a permissive attitude to children smoking were more likely to smoke.