This descriptive study aimed to (a) determine the extent of osteoporosis knowledge, perceived health beliefs, and self-efficacy with bone healthy behaviors in men with prostate cancer and survivors and (b) identify how dietary bone healthy behaviors are associated with these psychobehavioral and psychosocial factors. Three different questionnaires were used to measure osteoporosis knowledge, health beliefs, and self-efficacy in a group of men with prostate cancer and survivors. Bone health was assessed via dual-energy X-ray absorptiometry and calcium intake using a diet history. The prevalence of osteoporosis and low bone mass was high at over 70%. Participants had inadequate osteoporosis knowledge with a mean score of 43.3% (SD = 18%) on the Facts on Osteoporosis Quiz. Participants scored low on the subscale measuring barriers to exercise (median = 11; interquartile range [IQR] = 6.5), indicating minimal barriers to exercise participation, and the subscale measuring the benefits of exercise scored the highest (median = 24; IQR = 3.5) compared with the other subscales. Men with prostate cancer and survivors were highly confident in their exercise and calcium self-efficacy (83.0%, IQR = 24.0% and 85.7%, IQR = 27.0%, respectively). Participants did not meet their calcium requirements or consume enough dairy products for optimum bone health. Men with prostate cancer and survivors have poor osteoporosis knowledge, but are confident in their self-efficacy of undertaking bone healthy behaviors. This confidence did not translate to specific dietary behaviors as they did not meet their calcium or dairy intake requirements. Implications for cancer survivors is that there is a need for bone health education programs among prostate cancer survivors. These programs should go beyond education and empowerment to provide practical guidance to maximize uptake of bone healthy behaviors.