Purpose. To compare the rates of joint hypermobility in patients with and without anterior cruciate ligament (ACL) injury. Methods. Records of 135 men and 75 women (mean age, 24.6 years) who underwent ACL reconstructions were reviewed and compared with 55 male and 35 female controls with no knee injury. Joint hypermobility was evaluated by 2 examiners using the Beighton score. The maximum score was 9, and a score of ≥4 was defined as hypermobility. Results. The mean time from injury to presentation was 18 days. A non-contact mechanism of injury was more common. The inter-observer reliability was 0.7. 127 (60.5%) of the patients with ACL injury and 23 (25.5%) of the controls had hypermobility (p<0.01). Among them, 58% and 24% were men and 65% and 29% were women, respectively. Female gender was associated with hypermobility. Patients with ACL injury were more likely to have joint hypermobility with an odds ratio of 4.46. Conclusion. Joint hypermobility was more common in patients with ACL injury.