Excessive screen time is a significant risk factor for poor developmental health in several areas, including attention, sleep, and developmental milestones. Despite this finding, few studies have looked at either (i) the psychosocial and contextual antecedents of excessive screen time, or (ii) the indirect effects of environmental risk on developmental health via increased screen time. This study of 2568 women and their newborns (followed at ages 24, 36, and 60 months of age) found that higher levels of maternal depression and lower levels of maternal income and education predicted greater weekly screen time. Additionally, greater weekly screen time predicted greater inattention, delayed developmental milestones, and poorer sleep quality. There was no association between screen time and hyperactivity. Elevated screen time is one avenue through which the social determinant of health compromise child developmental outcomes.