Background <p>Rates of contralateral prophylactic mastectomy (CPM) for unilateral breast cancer have increased significantly. Decision aids (DAs) can support the shared decision-making process. This study systematically reviewed the literature to understand the feasibility and efficacy of using DAs to improve decision outcomes about CPM.</p> Methods <p>Six databases were searched through April 2024. Included studies reported on patient DAs about CPM after diagnosis of unilateral breast cancer for average- or low-risk patients. Two investigators reviewed 6186 abstracts and 155 full-text articles, extracting data for studies that met the criteria. Data quality assessment was performed using GRADE. </p> Results <p>The review included six studies published from 2017 to 2021. Four (66.7%) studies reported solely on patient acceptance of the DAs, whereas two (33.3%) studies included clinicians. Three (50%) DAs were formatted for online delivery, whereas two (33.3%) were formatted for paper delivery, and one (16.7%) was formatted for unknown delivery. Two (33.3%) research teams used a multi-disciplinary group to develop their DA. Overall, patient satisfaction with the DAs was high, and knowledge scores increased, but little consensus existed on when to introduce the DA. Important DA characteristics measured were use with or without a clinician, literacy considerations, and the order and balance of information.</p> Conclusions <p>More research should be conducted to develop and test DAs for CPM decisions, with attention to the balance of information, type of content, format, timing, and optimal delivery of such DAs. Future research in larger, multi-institutional populations using standardized, validated measures for satisfaction, values, decisional conflict, and health literacy could assess the impact of DAs for CPM.</p>