This systematic literature review aimed to examine the effects of Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR) head-mounted displays (HMDs) on patient understanding, satisfaction, and anxiety during preoperative informed consent. Following PRISMA-P guidelines (Prospero ID: CRD42023487281), we searched four major databases from their inception to March 24, 2023. Studies were eligible if they utilized VR, AR, or MR HMDs to visualize patient-specific data during informed consent across any medical specialty. Two reviewers independently conducted all steps of the systematic review process, and the risk of bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS). Sixteen studies involving a total of 1067 patients were identified and included. These comprised 10 Randomized Controlled Trials (RCTs) and 6 Non-Randomized Controlled Trials (non-RCTs), including one comparative study and five non-comparative studies. The literature reviewed was heterogeneous, encompassing patients with diverse conditions across various medical specialties, including cardiology, neurosurgery, transplantation surgery, vascular surgery, plastic surgery, and urology. The results demonstrated that VR, AR, and MR HMDs positively impact patient understanding, satisfaction, and anxiety reduction. Notably, the findings were more consistent for VR HMDs compared to the limited and variable literature on AR and MR HMDs. VR, AR, and MR HMDs generally show positive effects on patient understanding, satisfaction, and anxiety in preoperative informed consent. While VR HMDs consistently yield positive outcomes, further research is needed to elucidate the effectiveness and benefits of AR and MR HMDs in preoperative consultations.