Self-reported and measured weight and height were compared in a sample of adolescents aged 15 years (109 boys; 95 girls) and their parents (135 fathers; 190 mothers) recruited from secondary schools in the urban area of Geelong, Victoria, Australia. On average the adolescents' self-reported weight and height did not differ to a greater extent from the measured values than did that of their parents for their own weight and height but differences for individuals were much more variable. Self-reported weight was significantly underestimated and height over-estimated by both adolescents and parents. Body size had little effect on the extent of underestimation of weight and overestimation of height. The precision of reporting varied both with age and sex, while reporting bias in the parents, but not the adolescents', was influenced by father's occupation score. The educational level of the parents, however, had no statistically significant effect on reporting bias. The extent to which weight was underestimated and height overestimated was no greater than that observed in adults and suggests that group means reported for weight and height are likely to be as valid a measure of actual weight and height as in adults.