Background: The prevalence of obesity is increasing globally, both in developed and developing countries including Indonesia. Obesity occurs due to imbalance between energy in take and energy release for a long time as indicated by Body Mass Index (BMI). Someone is categorized as obese if he/she has BMI 95% percentil based on National Center for Health Statistics-Center for Disease Control. Risk factors of obesity are declining physical activity, declining fitness and negative body image. Besides, there are other factors such as genetics, food consumption, knowledge on nutrition and socialeconomic factor. Objective: To identify relationship between physical activity, fitness and body image and obesity among senior high school students at Banda Aceh Municipality. Method: The study was commenced from students screening to find out those who were obese and non obese based on the calculation of BMI. There were 82 obese students as cases and 82 non obese students as controls. Both cases and control had similar characteristics in terms of age, grade and school. The measurement of physical activity was done using International Physical Activity Questionnaire. Fitness was measured through walking/running test as long as 1.609 km, and body image was measured with Body Shape Questionnaire (BSQ). Result: There was relationship between physical activity and obesity (OR = 2, 100, 95% Cl; 1,032-4,272). This indicated that inactive students had risk 2.100 times greater for being obese than active students. There was relationship between fitness and obesity (OR= 2,467, 95% Cl; 1,205-5,051), this showed that unfit students had risk 2.467 times greater forbeing obese than fit students. There was relationship between body image and obesity. Students with BSQ quarter 2 (Q2) to quarter 3 (Q3) (OR = 10,459, 95% Cl; 1,381- 12,552), this indicated students had risk 10.459 times for being obese whereas students with BSQ quarter 4(Q4) (OR= 4, 163, 95% Cl; 1,381-12,552), this indicated students had risk 4.163 greater for being obese. Conclusion: Physical activity, fitness and body image were factor associated with prevalence of obesity among Senior High School students at Banda Aceh Municipality.