ObjectivesTo assess the frequency of anterolateral ligament (ALL) tears and ramp lesions (RL) detected with MRI in patients with anterior cruciate ligament (ACL) tears and to describe associated injuries indicative for these lesions.MethodsIn this retrospective study, 164 patients with surgically verified ACL tears were included. Preoperative MRI scans were reviewed for ALL tears and different types of RL. All coexisting meniscal tears, tears of the medial (MCL) and lateral collateral band (LCL), and posterior-medial tibial bone marrow edema (BME) were recorded. The frequency of ALL tears and RL was assessed and coexisting injuries were correlated using Pearson’s chi-square test. Ap< 0.05 was defined as statistically significant. In cases of multiple testing, Bonferroni’s correction was applied.ResultsALL tears and RL combined were detected in 28 patients (17.1%), ALL tears in 48 patients (29.3%), and RL in 54 patients (32.9%) which were significantly associated to each other. ALL tears were significantly associated with tears of the posterior horn of the lateral meniscus (PHLM), BME, and with tears of the LCL and MCL. RL were significantly associated with tears of the posterior horn of the medial (PHMM) and PHLM, with BME, and with tears of the LCL.ConclusionsACL tears are associated with RL or ALL tears in about one-third of cases and with both lesions combined in about one-fifth of cases. ALL tears and RL are significantly associated with additional posttraumatic injuries, which can thus be indicative of these lesions.Key Points• ACL tears were associated with ramp lesions or ALL tears in about one-third of the cases.• Ramp lesions and ALL tears were significantly associated with each other, tear in the PHLM, tear in the LCL, and BME.• ALL tears were more frequently associated with instable classified ramp lesion type 4b and type 5.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00330-023-09444-z.