Canadian data based on maternal reports for a nationally representative sample of 4,521 4-5-year-olds were used to examine associations among child care, family factors, and behaviors in preschool-aged children. Linear regressions testing for direct and moderated associations indicated that regulated home-based care was associated with less physical aggression and less prosocial behavior while high process quality in home-based care was associated with greater prosocial behavior. Among children in home-based settings, being in at least one additional current child care arrangement was linked with greater physical aggression, and low child care stability was linked to greater hyperactivity-inattention, internalizing behavior, and prosocial behaviors. For family factors, parenting behaviors and maternal depression were associated with greater behavioral problems while low household income was linked with greater hyperactivity-inattention among children in home-based care. There was a significant interaction between "process" quality and household income for physical aggression and internalizing behavior and between "structure" quality and parenting consistency for prosocial behavior for children in home-based care. Results suggest that child care matters for preschool behavioral outcomes, even after controlling for socio-demographic factors. High quality care appears particularly important for children in home-based care from low-income families so issues around child care quality and regulation should be considered. Findings also underscore the importance of family factors on young children's behaviors and show that child care and family influences work together to impact child outcomes. (Contains 3 tables and 3 figures.)