OBJECTIVE: To determine the association of psychological readiness to return to sports preoperative and 6 months post-reconstruction in athletes with anterior cruciate ligament (ACL) injury. DESIGN: Retrospective cohort study. SETTING: Clinical center of sports medicine. PARTICIPANTS: Fifty athletes, aged 16-45 years, were included in this study. Participants had a modified Tegner activity scale score ≥5 before ACL injury. MAIN OUTCOME MEASURES: Participants were divided into High and Low groups based on ACL-return to sport after injury scale (ACL-RSI) scores 6 months post-ACL reconstruction (ACLR) (cutoff: 56 points). RESULTS: The Low group had lower ACL-RSI scores than the High group preoperatively (P < 0.001) and 6 months post-ACLR (P < 0.001). The High group had a significantly greater amount of change in ACL-RSI scores preoperatively to 6 months post-ACLR than the Low group (P = 0.003). Preoperative ACL-RSI scores increased significantly to 6 months post-ACLR in the entire group of participants (P < 0.001) and in the High group (P < 0.001). However, in the Low group, ACL-RSI scores did not increase significantly (P = 0.714). CONCLUSIONS: Participants with low ACL-RSI scores 6 months post-ACLR had low preoperative ACL-RSI scores that did not improve preoperatively to 6 months post-ACLR.