BACKGROUND No previous study has evaluated the relationship between chronotype and adherence to the Mediterranean diet among adolescents. The aim of the present study was to assess the association between chronotype and adherence to the Mediterranean diet in a sample of Spanish adolescents aged 12-17 years. METHODS This study examined secondary data from 820 adolescents (55.5% girls) from the Eating Healthy and Daily Life Activities (EHDLA) study, which included a representative sample of adolescents aged 12-17 years from the Valle de Ricote (Region of Murcia, Spain). Adolescents' chronotype was evaluated with the Morningness/Eveningness Scale in Children. Adherence to the Mediterranean diet was determined through the Mediterranean Diet Quality Index for Children and Teenagers. RESULTS The proportion of adolescents with an optimal Mediterranean diet was 37.6%. In relation to chronotype, we found that 24.5%, 69.4%, and 6.1% of the adolescents were classified as morning, intermediate, and evening types, respectively. After adjusting for several covariates, both evening- and intermediate-type adolescents showed lower odds of having optimal adherence to the Mediterranean diet (evening-type: odds ratio [OR] = 0.30, confidence interval [CI] 95% 0.12-0.72; intermediate-type: OR = 0.62, CI 95% 0.44-0.87) than morning-type adolescents. CONCLUSIONS Chronotype could affect adherence to the Mediterranean Diet in adolescents, so it should be a factor to be considered in future studies assessing eating habits. CONCLUSIONS No previous study has evaluated the relationship between chronotype and adherence to the Mediterranean diet among adolescents. Both evening- and intermediate-type adolescents showed lower odds of having optimal Mediterranean diet adherence than morning-type adolescents. These findings may indicate a need to promote eating healthy habits based on a more holistic approach, not only on the total energy expenditure or in specific food groups but also on the chronotype.