A sample of 615 parents of 5-6-year-old children and 947 parents of 10-12-year-old children completed a questionnaire in Australia. Just over 50% of parents reported they were concerned their child was not getting enough activity. These findings suggest that parents who are concerned about their child’s physical activity levels provided a less supportive environment for physical activity than parents who are not concerned. The challenge for public health will be to harness parental concerns and translate them into action.