Identifying osteoporosis in geriatric populations is essential for fragility fracture prevention. While dual-energy X-ray absorptiometry (DXA) remains the gold standard for diagnosing osteoporosis, its availability and cost for mass screening are limited. This study aims to determine an effective fracture risk assessment tool (FRAX) cut-off value for screening osteoporosis in the Thai geriatric population. The demographic data, FRAX hip fracture (HF), major osteoporotic fracture (MOF), and Bone mineral density (BMD) of community-dwelling Thai adults aged ≥ 60 years, conducted between March 2021 to August 2022 were analyzed. Osteoporosis is defined as a BMD T-score ≤ - 2.5. The accuracy of FRAX in identifying osteoporosis was assessed using the area under the receiver operating characteristic curve (AUC). Among 2991 participants (average age 69.2 ± 6.5 years), the discriminative ability was acceptable for both FRAX hip fracture (HF) (AUC = 0.75) and major osteoporotic fracture (MOF) (AUC = 0.72). A cut-off value of 1.5 for FRAX HF and 4.5 for FRAX MOF demonstrated excellent sensitivity (90.4%) and a high negative predictive value (89.7%) in osteoporosis detection. This study identifies FRAX cut-off values that can effectively screen for high-risk osteoporosis in the Thai geriatric population and suggests that FRAX could be a valuable tool for initial osteoporosis screening in Thai seniors.