Objective: To explore the associations among achievement goal orientation, learning stress and sleep quality among middle school students. Methods: A total of 5 781 students were recruited from 14 middle schools in Guangzhou by a stratified cluster random sampling method. These students were investigated with learning stressors (SSA), achievement goal orientation (ADG), and Pittsburgh Sleep Quality Index (PSQI). Results: The mean score of four aspects of achievement goal orientation was as follows: performance approach (25.98±6.76), performance avoidance (15.52±4.12), mastery approach (25.87±6.77), mastery avoidance (15.19±4.12). The average score of learning stress and sleep quality was (149.53±42.46) and (6.45±2.86), respectively. Performance approach, mastery avoidance and performance avoidance positively associated with learning stress and sleep quality(r=0.12-0.53, P<0.01). Mastery approach was negatively correlated with learning stress and sleep quality (r=-0.14-0.22, P<0.01). Four types of achievement goal orientation both had a direct effect on sleep quality. Performance avoidance and mastery approach indirectly affected sleep quality through learning stress. Conclusion Achievement goal orientation of middle school students closely relates to learning stress and sleep quality; performance avoidance and mastery approach indirectly affects sleep quality through learning stress. Positive achievement goal orientation helps to reduce learning stress, which would lead to sleep quality improvement among middle school students.