INTRODUCTION Accurate parental perception of their child's weight is poor. Accuracy may be influenced by differences in ethnicity but this is currently unknown. AIM To determine whether agreement between parental perception of child weight status and actual child weight status differs according to ethnic group (NZ European, Māori, Pacific, Asian), and to investigate whether it is influenced by various demographic and behavioural factors. METHODS A total of 1093 children (4-8 years old) attended a weight screening initiative. Parents completed questionnaires on demographics, beliefs about child weight, parenting style, parental feeding practices and social desirability. Actual measured weight status was compared with parental perception of weight status (underweight, normal weight, overweight). RESULTS Agreement about child weight status was apparent in 85% of NZ European, 84% of Māori, 82% of Pacific and 88% of Asian children. However, adjusting for chance led to kappas of 0.34, 0.38, 0.41 and 0.53, respectively, indicating only fair-to-moderate agreement. Overall, agreement between measured body mass index and parental perception was not related to ethnic group, child sex and age, maternal age and education, and household deprivation (k ranged from 0.16 to 0.47). However, agreement about weight status was higher in parents who reported higher levels of restrictive feeding than in parents who reported less restriction (P < 0.01) but agreement was only fair. CONCLUSION Agreement between parental perception and actual weight status was fair and did not differ between the ethnic groups examined.