The purpose of this study was to determine the effect of socioeconomic status (SES) and social comparisons on body perception, and to identify their relationship to unhealthy behaviours and changing body structures, by assessing body perception in youths. A questionnaire was administered to 640 university students. The topics covered included SES, body definitions, behaviours related to body weight (such as exercise, dieting, starving, using diet foods, drug use, and bingeing and purging) and a social comparison scale. The prevalence of heavy exercise (42.9%) among male students was significantly higher in the low-income group (p<0.01), whereas it was significantly higher (61.7%) among female students in the high-income group (p<0.001). Behaviours such as dieting and starving for more than 24 hours were more common among female students in the high-income group (p<0.01). The average social comparison scores were significantly lower among students with a higher body mass index. The social attractiveness subscale scores were significantly lower (p<0.05) among students with unhealthy body definitions. The components of attractivity showed a clear correlation among students with unhealthy body definitions. As well as the increasing prevalence of obesity in developing countries, unnecessary body-measurement controls and »ideal« body images are affecting the behaviour of youths. Gender is related to most of these behaviours. Understanding the relationship between social comparisons and body appearance in adolescent females and males can be facilitated by examining certain features of attractiveness.