<b>Background </b><br /> The increase in the prevalence of obesity and overweight is a global trend, whereas the number of studies devoted to the psycho-social functioning of the overweight young is comparatively small. The objective of this study was to investigate the correlations between the occurrence of overweight and obesity during adolescence and achievement motivation and self-esteem levels, taking into consideration the sex and age of subjects.<br /> <br /> <b>Participants and procedure</b><br /> Altogether, 72 subjects were included in the study. Of them, 36 were overweight (n = 16; BMI = 25-29.9) or obese (n = 20; BMI ≥ 30), whereas the control group (n = 36) comprised individuals with standard body weight. Both the overweight/obese group and the control group were composed of 18 females and 18 males. The age range of subjects was 14-21 (M = 17.32; SD = 2.61). The M. Rosenberg Self-Esteem Scale, the Questionnaire of Measuring Achievement Motivation (by M. Widerszal-Bazyl), and also a socio-demographic survey, were applied.<br /> <br /> <b>Results</b><br /> Overweight and obese individuals are characterized by lower (average or low) self-esteem and achievement motivation (they are characterized by a lower perseverance level while performing tasks, perceive time in a less dynamic way, are less future-oriented, and their self-confidence level is lower) than individuals with standard body weight, and who are characterized by high self-esteem and average achievement motivation. In the scope of school mark average, and also of planning higher academic education, there are no intergroup differences. Sex, and also age, does not differentiate overweight or obese individuals in the scope of self-esteem or achievement motivation. Differences occur in the case of comparing individuals of the same sex. Overweight or obese women are characterized by a lower self-esteem level than those whose body mass index is normal. Overweight or obese men are characterized by a lower self-esteem and achievement motivation levels (apart from the above-mentioned indicators, they are characterized by a lower level of ability to delay gratification, and of striving for social recognition) than these whose body mass index is normal. <br /> <br /> <b>Conclusions</b><br /> Higher self-esteem occurs together with a stronger motivation achievement in the entire studied group. This correlation does not occur when the group of overweight and obese individuals, and also the control group, are considered separately. In the entire studied group, as well as in subgroups (of overweight and obese, and also of people with normal weight), there is no connection between self-esteem, mean school grades and planning higher academic education.