Introduction: The global increase in childhood overweight and obesity has been ascribed partly to increases in children's screen time. Parents have a large influence on their children's screen time. Studies investigating parenting and early childhood screen time are limited. In this study, we investigated associations of parenting style and the social and physical home environment on watching TV and using computers or game consoles among 5-year-old children. Methods: This study uses baseline data concerning 5-year-old children (n = 3067) collected for the 'Be active, eat right' study. Results: Children of parents with a higher score on the parenting style dimension involvement, were more likely to spend >30 min/day on computers or game consoles. Overall, families with an authoritative or authoritarian parenting style had lower percentages of children's screen time compared to families with an indulgent or neglectful style, but no significant difference in OR was found. In families with rules about screen time, children were less likely to watch TV>2 hrs/day and more likely to spend >30 min/day on computers or game consoles. The number of TVs and computers or game consoles in the household was positively associated with screen time, and children with a TV or computer or game console in their bedroom were more likely to watch TV>2 hrs/day or spend >30 min/day on computers or game consoles. Conclusion: The magnitude of the association between parenting style and screen time of 5-year-olds was found to be relatively modest. The associations found between the social and physical environment and children's screen time are independent of parenting style. Interventions to reduce children's screen time might be most effective when they support parents specifically with introducing family rules related to screen time and prevent the presence of a TV or computer or game console in the child's room.