A comparative study was undertaken to assess the nutritional status, dietary practices and physical activities of school going adolescents in public and private schools (PPSs) of Karachi, Pakistan. A sample of 101 boys and 100 girls from PPSs was randomly selected for their weight,height, waist and hip circumferences, percent body fat and lean body mass measurements. Adolescent boys and girls were interviewed for their dietary practices, socio-economic status, frequency and type of physical activities and their responses were recorded. Results by gender and school type revealed that both the boys and girls of private schools had a significantly lower mean age but significantly higher mean height-for-age Z-score, waist and hip circumferences than the public school adolescents. Food frequency results revealed that the frequency and patterns of breakfast, break-time snack, lunch and dinner of private school going adolescents were more diverse and nutritiously rich. Skipping breakfast was more common among adolescents being higher in girls than boys. Parents of adolescents belonging to private schools had a higher education and socio-economic status. Private school adolescents were physically more active (p<0.05) in terms of frequency and type of physical activities. The study concludes that the adolescents of private schools had a better nutritional status, consumed food and beverages of better quality and were physically more active. However, boys and girls of both the public and private schools failed to meet the national and international dietary guidelines of recommended food servings.