OBJECTIVES: To examine parent closeness and its effect in predicting youth smoking when 0, 1, or 2 parents smoked. METHODS: Youth and parent smoking, closeness to parents, family structure, and gender and ethnicity among middle (n=17,468) and high school (n=5457) students were measured using a questionnaire. RESULTS: Number of parents smoking incrementally moderated the protective effect of all 4 measures of parent closeness, in predicting youth smoking. CONCLUSIONS: Addressing parent smoking and strengthening family relationships need significantly greater emphasis in interventions to further reduce youth smoking.