The present study examined adolescents' actual and perceived weights in relation to why adolescents think they weigh what they do, where adolescents obtain weight control information, and adolescents' weight locus of control. The study was conducted in a Midwestern high school, based on information obtaind from 194 freshmen. Thirty percent of the adolescents perceived their weight category inaccurately when compared to their actual weight and height. One-third of those who were thin, one-half of those who were normal weight, and two-thirds of those who were heavy had been exercising during the past six months to control or lose weight. Six percent of the thin, 41% of the normal weight, and 56% of the heavy students had dieted within the past six months to control or lose weight. The leading sources of weight control information were television, family, friends, and magazines. Teachers were identified as sources of information by less than 10% of the students. Mother, family, and friends were identified as those most helpful in adolescents' attempts to lose weight. Significant chi-square differences were found between weight locus of control orientations and actual and perceived weight categories. Finally, a multivariate analysis of variance was used to analyze adolescents' perceptions of weighing what they do. Eat too much vs too little and exercise too much vs too little were the two reasons identified that were statistically significant. The information obtained from this study may be useful in designing and implementing weight control and nutritional programs for adolescents. For many of the adolescents, their perceptions were different from reality.