In music education, assessing learners’ musicality has long been considered vital for understanding individual aptitudes and designing effective instruction. Müllensiefen et al. (2013) introduced the concept of musical sophistication to explain how musical ability manifests in performance, perception, personal values, experience seeking, and engagement in musical activities. Based on this concept, the Goldsmiths Musical Sophistication Index (Gold-MSI; Müllensiefen et al., 2014)—a 38-item self-report measure—assesses musical skills and behaviors across various age groups, musical preferences, and majors, and is widely used across cultures. However, research on the related factors remains limited, and translation and adaptation into various languages are essential for cross-cultural comparison and broader application. The purpose of this study was to validate the Korean version of the Gold-MSI (Gold-MSI-K) and to analyze the relationships between musical sophistication and various sociodemographic and musical background variables, including gender, age, years of education, income, music major status, preferred genre, and primary instrument.The Gold-MSI-K was developed through five stages, including translation, item modification, and expert review. Data analyses were conducted using IBM SPSS ver. 26.0, AMOS ver. 21.0, and the psych and GPArotation packages in R ver. 4.4.2. The Gold-MSI-K data were collected over ten days (November 10-20, 2024) via a Google Forms link shared through social networks. Confirmatory factor analysis (CFA) and model fit comparisons using a Korean adult sample (N = 712, aged 18-80) showed that a bifactor model with one general and five subfactors (Active Engagement, Perceptual Abilities, Musical Training, Singing Abilities, and Emotions) provided the best fit. This structure closely matched the original English version (Müllensiefen et al., 2014) and outperformed other national models. Internal consistency (α = .82-.93, ωₜ = .87-.95, λ₆ = .81-.94) and test-retest reliability (r = .85-.92) were both excellent.Our study found that individual differences in Gold-MSI-K scores were linked to sociodemographic variables. Females scored higher on musical training and emotional engagement, whereas males showed greater active engagement. Younger participants exhibited higher emotional and active engagement but lower perceptual abilities. Higher education and income were associated with higher scores in training and perception, and music majors showed greater musical sophistication. Classical listeners scored higher in perception and training, while K-pop listeners showed greater active engagement. This study provides a reliable tool for assessing musical sophistication in Korean speakers and supports the cross-cultural applicability of the Gold-MSI.