Purpose This study aimed to identify independent predictive factors for return to sports (RTS) after anterior cruciate ligament (ACL) reconstruction in competitive-level athletes and to determine optimal cut-off values for these factors at 6 months after surgery. Methods A total of 124 competitive athletes (50 males and 74 females; mean age, 17.0 years; preinjury Tegner activity scale > 7) who underwent primary ACL reconstruction were enrolled. Assessments at 6 months after surgery consisted of knee functional tests quadriceps index, hamstrings index, and single-leg hop for distance (SLH) and 2 self-report questionnaires IKDC subjective score and ACL-Return to Sport after Injury scale (ACL-RSI). At 1 year after surgery, athletes were classified into the RTS group ( n  = 101) or non-RTS group ( n  = 23) based on self-reported sports activities. After screening possible predictive factors of RTS, multivariate logistic regression and receiver operating characteristic curve analyses were performed to identify independent factors. Results Multivariate logistic regression analysis identified SLH (odds ratio, 2.861 per 10 unit increase; P  < 0.001) and ACL-RSI (odds ratio, 1.810 per 10 unit increase; P  = 0.001) at 6 months as independent predictors of RTS at 1 year after surgery. Optimal cut-off values of SLH and ACL-RSI were 81.3% (sensitivity = 0.891; specificity = 0.609) and 55 points (sensitivity = 0.693; specificity = 0.826), respectively. Conclusion In competitive athletes, SLH < 81% and ACL-RSI < 55 points at 6 months after surgery were associated with a greater risk of unsuccessful RTS at 1 year after surgery. SLH and ACL-RSI at 6 months could serve as screening tools to identify athletes who have difficulties with returning to sports after ACL reconstruction. Level of evidence III.