Objectives: This study was conducted to identify the association among vitamin D and osteoporosis, sarcopenia, osteosarcopenia in adults ≥50 years old using the 2009-2011 Korea National Health and Nutrition Survey. Methods: This study involved 6,635 (2,908 males and 3,727 females) participants in the 2009-2011 KNHANES aged 50 years or older. Bone mineral density and appendicular skeletal muscle mass (ASM) was measured by dual X-ray absorptiometry. Sarcopenia was defined as an ASM divided by body mass index (BMI) (ASM [kg]÷BMI [kg/m2]) value of <0.789 in males and <0.512 in females and osteoporosis was defined as T-score <-2.5 at lumbar or femur neck. Osteosarcopenia was defined as having osteoporosis and sarcopenia. Results: After adjusting for covariates and parathyroid hormone, the level of vitamin D was negatively associated with osteoporosis at femur neck (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.02-2.77 for <10.0 vs. ≥30.0, OR 1.45, 95% CI 1.02-2.06 for 10.0-19.9 vs. ≥30.0) sarcopenia (OR 1.92, 95% CI 1.11-3.34 for <10.0 vs. ≥30.0) and osteosarcopenia (OR 2.28, 95% CI 1.06-4.90 for <10.0 vs. ≥30.0). Conclusions: There were significant associations of vitamin D with osteoporosis, sarcopenia and osteosarcopenia independent of PTH in Korean adults 50 years old and over.