OBJECTIVE: To systematically review randomized controlled trials and clinical controlled trials evaluating the effectiveness of Decision Aids (DAs) compared to usual care or alternative interventions for older patients facing treatment, screening, or care decisions. METHODS: A systematic search of several databases was conducted. Eligible studies included patients ≥ 65 years or reported a mean of ≥ 70 years. Primary outcomes were attributes of the choice made and decision making process, user experience and ways in which DAs were tailored to older patients. Meta-analysis was conducted, if possible, or outcomes were synthesized descriptively. RESULTS: Overall, 15 studies were included. Using DAs were effective in increasing knowledge (SMD 0.90; 95% CI [0.48, 1.32]), decreasing decisional conflict (SMD -0.15; 95% CI [-0.29, -0.01]), improving patient-provider communication (RR 1.67; 95% CI [1.21, 2.29]), and preparing patients to make an individualized decision (MD 35.7%; 95% CI [26.8, 44.6]). Nine studies provided details on how the DA was tailored to older patients. CONCLUSION: This review shows a number of favourable results for the effectiveness of DAs in decision making with older patients. PRACTICE IMPLICATIONS: Current DAs can be used to support shared decision making with older patients when faced with treatment, screening or care decisions.