Online education transforms many aspects of teaching and learning in higher education. International students studying abroad already face considerable stress and negative emotions, and the transition to online learning can further intensify their learning anxiety. This study systematically investigated the factors associated with international students' online learning anxiety by integrating demographic, adjustment, and online learning readiness-related factors. A sample of 380 Chinese students studying in South Korea was investigated. A three-step hierarchical multivariate regression revealed that doctoral students demonstrated significantly lower learning anxiety levels compared to freshmen. Adjustment-related factors explained significant additional variance in online learning anxiety, with length of stay, social support and language proficiency emerging as significant predictors. Online learning readiness-related factors were found to be the most powerful predictors in explaining learning anxiety, with self-directed learning, learner control, computer/internet self-efficacy and online communication self-efficacy being significant predictors. The findings were discussed, and future research implications were suggested.