Objective Examine the associations between caregiver health literacy (HL) and smoking-related outcome expectancies, implementation of home/car smoking bans (H/CSBs), and child secondhand smoke exposure (SHSe). Methods Caregivers of Head Start children residing with a smoker(s) completed measures assessing HL, outcome expectancies, and H/CSB implementation. Biomarkers of child SHSe included home air nicotine monitors and child salivary cotinine. Results Caregivers with lower HL had higher levels of home air nicotine and child salivary cotinine in the full sample and among smokers. After controlling for child age and number of smokers in the home, lower HL was associated with higher endorsement of negative smoking expectancies in the full sample and in smokers. HL was not associated with H/CSB implementation across groups. Conclusions Caregiver HL is associated with child SHSe and is important in shaping smoking-related beliefs. HL is not directly related to adoption of SHSe-reduction behaviors such as H/CSBs.