Osteoporosis is the most common metabolic bone disease. Preventive behaviors are simple and efficient methods that can help in osteoporosis prevention and promotion of health. Aim: This study aimed to evaluate the effect of educational program based on theory of planned behavior for female teachers regarding osteoporosis prevention. Design: A quasi-experimental research design was employed in this study. Setting: The study was done at seven Preparatory Schools affiliated to Benha Educational Administration. Sample: Simple random sample of 126 female teachers divided into study and control groups, each group had 63 female teachers. Tools: Two tools were used I: A structured questionnaire to assess female teachers’ demographic characteristics, reproductive history, family and medical history, female teachers’ knowledge and reported practices about osteoporosis prevention. II: Theory of planned behavior to assess female teachers’ attitude, perceived behavioral control, subjective norms and behavioral intention regarding osteoporosis prevention. Results: A highly significant difference on the total levels of knowledge, reported practices and planned behaviors of the study group was noticed post program. Also, planned behavior score post educational program implementation regarding osteoporosis prevention was best predicted among study group by marital status, residence, monthly income, family history, total knowledge and reported practices