Increased physical inactivity and sedentary behavior among children are a global health concern. Examine associations between parents' perceived neighborhood environment and children's physical activity, outside time, and screen time, and whether these associations were moderated by age and socioeconomic position (SEP). Parents (N = 1212) completed a survey during the Recording and EValuating Activity in a Modified Park study. The neighborhood perceptions (social and physical environment), children's age, physical activity, outside time, and screen time were parent-reported. The SEP was derived from the Index of Relative Socio-economic Advantage and Disadvantage. Multiple linear and logistic regressions were performed with age and SEP interactions. Favorable perceptions of opportunities to be active and exercise were associated with a higher likelihood of meeting physical activity guidelines. Favorable perceptions of neighborhood ease for walking and a larger social network were also associated with more outdoor time. Moderation analyses revealed that favorable perceptions of several physical and social neighborhood environment features were associated with a higher likelihood of meeting physical activity guidelines in the high-SEP group and were negatively associated with preschoolers' weekday screen time. Future neighborhood environment initiatives and interventions aiming to promote active living communities should consider differences in age and SEP.