The objective of this observational study was to examine the association between appendicular lean mass and frailty in adults aged 60 years and older. This study was conducted in the Outpatient Department of the National Geriatric Hospital in Hanoi, Vietnam. Appendicular lean mass (kg) was assessed by using Dual energy X-ray absorptiometry scans. Frailty was defined according to Fried’s frailty criteria. A total of 560 outpatients were included in the study, with a mean age of 70 years. The prevalence of frailty was 12.0%. Frail patients had significantly lower appendicular lean mass compared with non-frail outpatients (9.6 ± 2.0 kg vs. 11.7 ± 3.1 kg, p<0.001). On multivariable logistic regression models, higher appendicular lean mass was associated with significantly reduced odds for frailty (adjusted OR = 0.74, 95%CI 0.59–0.93). These findings suggest that the assessment of appendicular lean mass should be considered in older patients attending outpatient geriatric clinics.