When side-step cutting and landing maneuvers are performed under unanticipated conditions, commonly seen in sports, trunk and lower limb biomechanics are often altered. These biomechanical alterations in the trunk, hip, knee, and ankle may increase the risk of anterior cruciate ligament (ACL) injuries. The aim of this systematic review with meta-analysis was to synthesize the effects of unanticipated side-step cutting and landing on trunk and lower limb biomechanics and evaluate potential implications for ACL injury risks. We searched PubMed, Web of Science, and EBSCO from inception to June 2024. Standardized mean differences (SMD) with 95 % confidence intervals (CIs) were calculated. This review of 35 studies, with a methodological quality score of 9.26 ± 0.78, found that unanticipated side-step cutting increased lateral trunk flexion angles away from the intended direction at initial contact, peak knee flexion angles, and peak external hip flexion, hip abduction, and knee abduction moments. Additionally, unanticipated side-step cutting decreased the knee flexor–extensor directed co-activation ratio during pre-contact. Unanticipated landing decreased hip and knee flexion angles at initial contact, but increased hip internal rotation angles at initial contact and peak external hip internal rotation moments. Our findings highlight the specific alterations in trunk and lower limb biomechanics due to unanticipated side-step cutting and landing maneuvers, which are relevant to the development of ACL injuries. Effective risk assessment and rehabilitation programs must consider the impact of these unanticipated movements, which are prevalent in many sports.