This study examines the determinants of tourism human resource quality in the mountainous areas of Quang Ngai Province - an ethnically diverse highland destination in central Vietnam where community-based and indigenous cultural tourism constitute the primary development trajectory. Grounded in an integrated theoretical framework drawing on human capital theory, the ability–motivation–opportunity model, human resource development theory and social exchange theory, the study proposes and tests a structural model in which five organisational and individual determinants - training and development, accumulated education and experience, compensation and incentives, work environment, and organisational support - influence tourism human resource quality both directly and indirectly through work motivation and job satisfaction as dual mediators. Survey data collected from 385 tourism workers employed in accommodation, tour operation and visitor attraction establishments across the highland sub-region were analysed using partial least squares structural equation modelling. All five determinants exert statistically significant positive effects on tourism human resource quality. Accumulated education and experience produces the largest direct effect (β = 0.207), an outcome explained through the mechanism of indigenous knowledge capital accumulation identified in the companion qualitative study. Work motivation mediates the effects of training and development, compensation and incentives, and organisational support; job satisfaction mediates the effects of work environment and organisational support. The total indirect effect via dual mediation is substantial and comparable in magnitude to the direct structural effects, confirming that motivation and satisfaction are not mere outcomes of the determinants studied but active transmission mechanisms through which organisational practices translate into improved workforce quality. These findings carry specific implications for training reform, human resource policy and tourism development strategy in highland indigenous tourism destinations.