Objective The study aims to identify the nutritional habits of second-year high school students in Seferihisar, Turkey, and the factors associated thereof, based on the Ecological Framework. Methods In this cross-sectional study by a self-reported questionnaire, second-year high school students (n=392) attending public schools in Seferihisar had their nutritional habits measured with the Adolescent Food Habits Checklist scale. The food habit score was calculated and associated factors were evaluated in 4 layers based on the Mary Story’s Ecological Framework (individual factors, social, physical and macro-level environments). The data analysis for the association of these layers with the food habits score was executed through multi-level linear regression. Results Students’ participation rate was 87.7% (n=344). Of all the layers (from individual factors to the influence of the social environment and macro-level environment: nutritional literacy, the food consumption of their peers at school, availability of fruits-vegetables at home, buying junk food at the school canteen, presence of posters at school, etc.), the option for advertised food items was statistically explanatory based on the linear regression analysis (p<0.05). Conclusions The model derived from the Ecological Framework explained 45% of the nutritional habits with an equivalent contribution from the four layers. Availability of healthy food items where the students lived and higher levels of nutritional literacy led to healthy nutritional habits. Having healthy food items sold at school canteens at affordable prices, using posters to promote a healthy diet, and introducing nutrition-related courses into the curricula would support students in developing healthy nutritional habits.