For pregnant women and their fetus, secondhand smoking poses major public health effects. This study analyzes the determinants of change in smoking behavior among fathers whose partners were pregnant. The study is a secondary analysis of a nationally representative Lebanese cross-sectional survey of 1,028 households conducted in 2007. Currently smoking fathers with a child of 5 years of age or less were included. The main outcome was the change in the father's smoking behavior during his wife's last pregnancy. The study concluded that fathers who changed their smoking patterns when their wives were pregnant were significantly more educated, more likely to smoke a lesser number of cigarettes per day (OR = 96, 95% CI (0.93, 0.99)), and more knowledgeable about cigarette constitutes and its health risks (OR = 1.37, 95% CI (1.08, 1.74). Public health practitioners and health professionals are recommended to raise awareness and provide cessation programs for parents and especially fathers.