Introduction and objective: The perception of one’s own body is determined by many factors, including gender, media, societal expectations, and the quality of life. The aim of this study was to assess how young people from the Silesian Voivodeship perceive their own bodies in relation to weight and gender. Materials and methods: The study involved 560 (100%) female and male secondary school students in the Silesian Voivodeship. The subjects were aged 16 to 18 (x̄ = 17.19 ± 0.8). The study used a proprietary questionnaire consisting of questions regarding the basic data of the surveyed adolescents and their body weight and height, as well as the Polish version of the Body Esteem Scale (BES). Results: Spearman’s rank correlation test showed a statistically significant negative relationship between body mass index (BMI) and scores on the “Physical Condition” subscale (p < 0.012) in the subgroup of boys and a statistically significant negative relationship between BMI and scores on the “Sexual Attractiveness” (p = 0.021) and “Weight Control” (p < 0.0001) subscales in the subgroup of girls. Conclusions: An increase in BMI negatively affects body perception among young people in the Silesian Voivodeship, causing a decrease in self-esteem. Girls with increased BMI focus on the negative perception of body parts that can be changed through physical exercise or diet. Boys, on the other hand, base their self-esteem on parameters related to endurance, agility, strength and functionality, and efficiency, and not necessarily on appearance.