Background: Osteoporosis is becoming more common, especially among women. Prevention through educational initiatives is the best way to lower the disease burden. Objective: To estimate perimenopausal women's knowledge and attitudes concerning osteoporosis and their relation to specific sociodemographic characteristics. Methods: 391 perimenopausal women who were utilizing the outpatient clinic facilities at the hospitals in Al-Najaf City participated in a cross-sectional study. Starting in May 2022, data was gathered for six months. Data were gathered using a questionnaire that asked about sociodemographic factors, the Osteoporosis Knowledge Assessment Tool, and the Osteoporosis Health Belief Scale. Results: In this study, a substantial proportion of the participants have poor knowledge (61.89%), while average and good knowledge encompass 31.97% and 6.10% of the participants, respectively. The mean score for osteoporosis knowledge was 7.18±3.49. About osteoporosis health beliefs, the best belief of women is in perceiving the benefits of calcium intake; the mean score was 20.32±4.69. A significant positive correlation (p<0.001) was found between knowledge and exercise benefits, calcium intake benefits, perceived severity, and health motivation, whereas a significant negative correlation (p<0.001) was found between knowledge and barriers to calcium intake and exercise. Conclusion: The participants have below-average knowledge and beliefs regarding osteoporosis. Knowledge of osteoporosis correlates positively with health beliefs, including perceived susceptibility, health motivation, the benefit of calcium intake, and the benefit of exercise, whereas it correlates negatively with barriers to calcium and barriers to exercise.