Self-esteem is a global, one-dimensional and relatively stable construct regarding a positive or negative judgment towards oneself (Rosenberg, 1965). There is evidence that low self-esteem is associated with unhealthy eating behaviours. The recent meta-analysis of longitudinal studies (Krauss et al., 2023), includingdata from more than 19,000 participants, has found that self-esteem negatively predicted total eating pathology over time and total eating pathology negativelypredicted self-esteem over time. It has been suggested that increased self-esteem regarding adherence to the diet characterises individuals with orthorexianervosa (Bratman & Knight, 2000). Therefore, it is essential to know if this factor might influence the development of orthorexia nervosa. Thus far, few studies have focused on the relationship between orthorexia nervosa and self-esteem. Moreover, there are contradictory results (Table 8.1). Self-esteem was found generally to be unrelated to orthorexia nervosa among university students of health education in Turkey (Özenoğlu & Ünal, 2015), adults in Australia (Barnes & Caltabiano, 2017), adults in Turkey (Yılmaz & Dundar, 2022), and college students in the United States of America (Oberle, Samaghabadi & Hughes, 2017). However, two studies have found that both higher trait self-esteem (Haddad et al., 2019) and higher state self-esteem (Sfeir et al., 2022) were linked to lower levels of orthorexia nervosa in a representative sample of the Lebanese population. Another study has also demonstrated that having high self-esteem reduces the tendency to healthy eating obsession (Yılmaz & Dundar, 2022).