Although elevated serum gamma-glutamyl transferase activity (GGT) has been linked with metabolic risk factors for sarcopenia, including non-alcoholic fatty liver disease, adiposity, and insulin resistance, whether GGT independently associated with sarcopenia and sarcopenic obesity has not yet been investigated. We analyzed cross-sectional data of 3,193 community-dwelling adults (42.2% men, age 63.4 ± 8.7) aged ≥50 years from the Fifth Korean National Health and Nutrition Examination Survey, 2010-2011. Sarcopenia was defined as a calculated value of the appendicular skeletal muscle mass divided by body weight (ASM/Wt, %) <1 standard deviation below the sex-specific mean for healthy young adults. Sarcopenic obesity was defined as sarcopenia combined with a waist circumference ≥90 cm for men and ≥85 cm for women. The prevalence of sarcopenia and sarcopenic obesity increased stepwise from the lowest to highest GGT quintiles (sarcopenia, 20.2-39.7%; sarcopenic obesity, 7.5-27.3%; P for trend, <0.001). Serum GGT activity was associated negatively with ASM and positively with waist circumference. In multivariate logistic regression analyses, participants in the highest GGT quintile had a 2.3-fold increased risk of sarcopenia and 3.4-fold risk of sarcopenic obesity versus those in the lowest quintile, whereas each single-unit increase in natural log-GGT associated independently with a 35% increased risk of sarcopenia and 62% increased risk of sarcopenic obesity after adjusting for age, sex, body mass index, and other confounders. Elevated serum GGT activity was independently associated with sarcopenia and sarcopenic obesity in community-dwelling older adults.