Obesity in adolescents show high prevalence specially in developing countries. Although birth order and sibling size have been mathematically coupled and in spite of their respective effect on both overweight and obesity, they have not been estimated before separately. Moreover, the educational achievement of parents might have impact on their children's nutritional status. ObjectiveThis study aims to assess how birth order and number of siblings affect adolescent obesity risk and to examine the impact of parent's education on adolescent obesity, the results will indicate which family members may be prioritized for inclusion in adolescent obesity prevention programs. Methodology A self-administered questionnaire was used to collect data on 90 adolescent aged 10 to 18 years old. It included sex, age, birth weight, birth order, number of siblings, lifestyle, and parents' educational level by a self-administered questionnaire completed by an adult member of the family.Adolescences' height and weight were done at nutrition and immunity clinic,Medical Research Centre of Excellence. The Centre of Disease Control's (CDC) BMI cut-off points were used to classify cases as normal (5–84^th percentile) or obese (≥95th percentile). Results Adolescent's BMI was not associated with neither parent's education nor birth order. Distribution of the number of siblings was different in both groups as regards BMI but with no statistical significance. Conclusion The study showed no association between adolescent's BMI and parent's education or order of birth. There was no significant association between number of their siblings and the development of obesity.