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<div><p>Females are at greatest risk for reinjury after return to sport (RTS) following anterior cruciate ligament (ACL) reconstruction (ACLR). The reasons for these sex differences, however, remain unclear. Psychological factors such as kinesiophobia have been identified as a potential predictor for reinjury following RTS. Studies investigating kinesiophobia have identified sex differences, yet whether this holds in the ACLR population remains unknown. The purpose of this study was to examine whether there are sex differences in kinesiophobia and other psychological factors, such as readiness to RTS and self-reported pain in the ACLR population. A total of 20 participants, eleven males (23.0 ± 8.4 years, 178.9 ± 7.6 cm, 76.8 ± 10.4 kg) and 9 females (19.6 ± 5.3 years, 165.1 ± 4.0 cm, 73.2 ± 25.0 kg) voluntarily participated in this study. The Tampa Scale for Kinesiophobia (TSK-11), Anterior Cruciate Ligament Return to Sport After Injury (ACL-RSI) scale, and self-reported pain using a visual analog scale (VAS) were administered after clearance for RTS (10.5 ± 2.3 months post-ACLR). Statistical significance was set <i>a priori</i> at p<0.05. A significant difference between sexes was observed for the ACL-RSI with males reporting a significantly higher score (92.82±16.16) compared to females (77.0±15.54; p = 0.040). There were no significant differences between sexes for VAS for pain (males = 4.55 ± 6.50; females = 1.22 ± 3.31; p = 0.228) and TSK-11 (males = 18.73 ± 3.17; females = 19.67 ± 4.61; p = 0.596). The results of this study demonstrated males had significantly higher ACL-RSI scores than females, suggesting males may have higher psychological readiness following clearance for RTS. This study did not demonstrate significant differences between sexes for kinesiophobia or pain level. Caution in interpretation of results is warranted due to the small sample size, highlighting the need for further research in this area.</p></div>