Objective: there may be age-related differences in the impact of weight change on health. This study systematically reviewed the evidence on the relationship between weight change and all-cause mortality in adults aged 65 years and older., Methods: MEDLINE, EMBASE and CINAHL were searched from inception to 11 June 2020, PROSPERO CRD 42019142268. We included observational studies reporting on the association between weight change and all-cause mortality in older community-dwelling adults. A random-effects meta-analysis was performed to calculate pooled hazard ratios and scored based on the Agency for Healthcare Research and Quality guidelines., Results: a total of 30 studies, including 1,219,279 participants with 69,255 deaths, demonstrated that weight loss was associated with a 59% increase in mortality risk (hazard ratio (HR): 1.59; 95% confidence interval (CI): 1.45-1.74; P < 0.001). Twenty-seven studies that reported outcomes for weight gain (1,210,116 participants with 65,481 deaths) indicated that weight gain was associated with a 10% increase in all-cause mortality (HR: 1.10; 95%CI: 1.02, 1.17; P = 0.01). Four studies investigated weight fluctuation (2,283 events among 6,901 participants), which was associated with a 63% increased mortality risk (HR: 1.66; 95%CI: 1.28, 2.15). No evidence of publication bias was observed (all P > 0.05)., Conclusion: for community-dwelling older adults, weight changes (weight loss, gain or weight fluctuation) are associated with an increased risk of all-cause mortality risk relative to stable weight. Further research is needed to determine whether these associations vary depending upon initial weight, and whether or not the weight loss/gain was intentional., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)