The aim of this thesis was to investigate the contribution of perfectionism, self-control, and conscientiousness in explaining the tendency to develop orthorexia nervosa in men and women. This research sought to examine whether there is a gender difference in the propensity to develop orthorexia nervosa, to establish the relationship between perfectionism, self-control, conscientiousness, and the level of orthorexia nervosa symptoms, and to explore the predictive contribution of perfectionism, self-control, and conscientiousness in explaining the tendency to develop orthorexia nervosa. The study was conducted on a sample of 287 participants, aged 18 to 30 years. The results of the research indicated that there was no statistically significant difference between men and women in the dimension of physical and psychosocial difficulties, emotional difficulties, or behaviors and preoccupation with healthy eating. However, for the latter dependent variable, a statistically significant difference was found at the 10% significance level. More precisely, men exhibited more frequent behaviors and preoccupation with healthy eating compared to women. The obtained results showed that the dimensions of orthorexia nervosa were generally weakly correlated with self-control, conscientiousness, and dimensions of perfectionism. Lastly, statistically significant first steps of regression models for the dimensions of orthorexia nervosa were found. The most prominent predictor of physical and psychosocial difficulties was parental criticism, while personal standards predicted preoccupation with healthy eating. Conscientiousness emerged as a key predictor of behaviors oriented toward healthy eating, while self-control predicted lower emotional difficulties.