OBJECTIVE. This was a descriptive study examining the psychological impact of a school-based, weight-screening intervention that included feedback to parents. METHODS. Children from years 3 and 6 (6–7 and 10–11 years old) in London schools were measured in school, and parents were sent information on the child's weight status. Children and parents completed questionnaires 6 weeks before and 4 weeks after the feedback; 358 children and 287 parents completed both questionnaires. The main outcome measures (parental feeding practices, parental perception of child weight, child body esteem, child eating behavior, and weight-related teasing) were assessed before and after feedback. Qualitative data on health-behavior change and parents’ and children's views of the measurement and feedback process were collected at follow-up. RESULTS. Fifty-one percent of the parents (n = 398) volunteered for child measurements and weight feedback. Feedback was not associated with changes in child feeding among parents of healthy-weight children, but dietary restriction increased in parents of overweight girls. Among healthy-weight children, restrained eating decreased and body esteem increased, but there were no significant changes among the overweight group and no changes in reports of teasing. Perceptions of child overweight did not increase significantly, but 50% of the parents of overweight children reported positive changes in health behaviors. The majority (65%) of parents wanted weight feedback on a regular basis, and most children enjoyed the measuring process. CONCLUSIONS. Weight feedback was acceptable to the majority of parents participating in an “opt-in” measurement and feedback program; adverse effects were minimal for children and parents, even when feedback indicated overweight. However, a minority of participants found it distressing, which highlights the importance of managing the process sensitively, particularly for families with overweight children.