Background: Osteoporosis is a preventable progressive metabolic disease. Girls have an increased risk of occurrence of osteoporosis in their old age. The BASNEF model can be employed to change behaviors related to health. Aim: The BASNEF model was employed to determine the predictors of osteoporosis preventive behaviors among adolescent girls. Method: This cross-sectional study was carried out on 209 adolescent girls selected from high schools in the Quchan County in 2016 using path analysis by stratified sampling. The data was collected through a demographic questionnaire and a 52-item researcher-made questionnaire, based on the BASNEF model constructs. The data was analysed using Shapiro-Wilk test, bootstrapping, and path analysis. Results: The average age of the students was 16.10 ± 0.59. The results of path analysis showed that Model 1 matched the BASNEF model relationships completely; however, it could not predict osteoporosis preventive behaviors. The constructs of model 2 (modified) was able to predict 50% of variances in osteoporosis preventive behaviors. There were positive and direct relationships between the following pairs of constructs: knowledge and attitudes (B=0.23, P<0.001); attitudes and the intention of osteoporosis preventive behaviors (B=0.37, P<0.001); subjective norms and the intention of osteoporosis preventive behaviors (B=0.53, P<0.001); behavioral intention and osteoporosis preventive behaviors (B=0.36, P<0.001); subjective norms and osteoporosis preventive behaviors (B=0.33, P<0.001), and enabling factors and osteoporosis preventive behaviors (B=0.29, P<0.001). Implications for practice: The community health nurse can use the constructs of the BASNEF model to change the osteoporosis preventive behaviors like knowledge, attitudes subjective norms and enabling factors.