Many children continue to be exposed to environmental tobacco smoke (ETS) each day. To describe the factors associated with providing a smoke-free home (PSFH) and vehicle (PSFV) for kindergarten children, a cross-sectional descriptive study was conducted in Manitoba, Canada, with 551 mothers and primary caregivers responding. A social-ecologic model of health behavior guided the study. In the bivariate analysis, being better educated, living with a partner, and having a higher income were associated with PSFH. In the multivariable logistic regression analysis, the variables most predictive for PSFH were living with a partner and the mother's self-efficacy, and for PSFV, the most predictive variables were the mother's self-efficacy and ETS knowledge. Smoking behaviors are complex and must be considered broadly within all levels of influence if nurses are to assist parents in protecting their children.