The present study, based on a cross-lagged panel design, was to examine the directionality of the relationships between anxiety, self-efficacy, and motivation in the context of online English learning. A total of 420 university students in China completed self-efficacy belief, motivation, and anxiety measures twice, eight months apart. The findings suggest that self-efficacy belief mediates the relationship between motivation and anxiety in online English learning, whereas anxiety mediates the relationship between self-efficacy belief and students' motivation. The mediation models based on two times of data collection achieved a satisfactory fit. However, the second model demonstrated a better model fit, highlighting the importance of anxiety in the relationship between motivation and self-efficacy beliefs. Understanding the causes and effects of anxiety for students may lead to training and resource development that are important to maintaining students' self-efficacy belief and motivation in online English learning.