Objective: The objective of the present study was to assess the nutritional status of adolescent girls and to investigate its association with socio-economic status, eating and physical activity pattern. Methods: A cross-sectional survey was conducted among adolescent girls (15 and 19 years) and stratified random sampling technique was done in 4 schools of Arar city, KSA. Subjects were asked to fill pre-tested questionnaire about socio-economic status, dietary and physical activity pattern and their height and weight were measured and BMI (kg/m2) was calculated. SPSS version 22 (2017) was used in entering, managing survey data and to analyze the obtained data. A p-value<0.05 was considered statistically significant for individual variables. Results: The final study sample consisted of 322 adolescent girls (response rate of 90.96%), with a mean age of 17.14 ± 1.15 years. More than one-fifth of the study population was overweight and obese, moreover, about three-fifth of the study population were of normal weight, while 19.2% were underweight. A significant relationship was observed between nutritional status with the mother’s occupation and education, family size, and a number of meals taken per day. Conclusion: Adolescent’s populations face two contrasting nutrition situations, under and over nutrition. This study will help in generating imperative data and recommendations for managing nutrition-related problems in adolescent girls in Saudi Arabia.