Studies on disordered eating behaviors (DEB) in multicultural populations with multiple religious/cultural affiliations are needed in order to clarify the relationship between cultural background and DEB. Therefore, we compared the presence of DEB among Christian and Muslim adolescents who share their school environment, controlling for the effect of body mass index, demographic variables and lifestyle habits. A sample of 493 girls and boys (339 Christian, 138 Muslim) whose mean (±SD) age was 14.8 (±1.7) years completed self-reporting questionnaires and underwent measurements of anthropometric data. Religious/cultural affiliation was defined by self-identification. The dependent variable, DEB was assessed by means of the Eating Disorders Inventory (EDI-2). Muslim girls and boys score higher than Christians on EDI-2 total scores, especially on the perfectionism subscale. Bivariate and multivariate analyses were used to determine the characteristics associated with DEB, which were detected in 24% of participants (19% of Christians and in 35% of Muslims). Among girls, DEB were directly associated with overweight or obesity, the presence of frequent quarrels with parents, academic failure and spending more than 3 h a day watching screen images. Among boys, DEB were directly associated with overweight or obesity and Muslim background; and inversely associated with age and socioeconomic status.