Abstract
A Canadian biennial youth survey facilitated repeating investigation of susceptibility to smoke and household socialization. We operationalized susceptibility to smoke by 3 levels on the basis of intention and behavior. Variables consistently predicting greater susceptibility across time and age groups were sibling smoking, household restrictions, and vehicle smoke exposure. Gender was predictive among older youths. Household restrictions and emerging legislation to ban smoking in vehicles with youth passengers provide protection against secondhand smoke exposure and sustained resolve to remain smoke-free.