This study was conducted to identify characteristics associated with treatment for osteoporosis among women aged 50 years and older in Japan and to explore differences among patients according to treatment regimen. Data were provided by a large annual survey representative of Japanese aged 18 and older; all measures were by self-report. Women aged 50 and older who reported diagnosed osteoporosis (N = 900) were compared based on current treatment status using bivariate statistics and logistic regression. Approximately 1 in 3 women in this study reporting diagnosed osteoporosis were currently untreated. Factors associated with current treatment for osteoporosis included having ≥1 physician visit in the prior 6 months (OR = 5.4, P < 0.001), self-rated moderate or severe osteoporosis (OR = 2.8, P < 0.001), completion of menopause (OR = 1.6, P < 0.05), and family history of osteoporosis (OR = 1.5, P < 0.05), while longer duration of osteoporosis diagnosis (OR = 0.9, P < 0.05) and arthritis (OR = 0.7, P < 0.05) were associated with lower odds of treatment. These findings suggest that diagnosed patients are not being actively managed in the longer term, and efforts need to be made to ensure that patients stay engaged with their healthcare providers.